You’ve probably seen the ads. A sleek, D-shaped robot glides effortlessly into a corner, sucks up a mountain of pet hair, and then disappears into a clean-looking base station. It looks like magic. But honestly? The iRobot Roomba s9+ isn't magic—it’s just a very aggressive piece of engineering. When it launched, it was the most expensive vacuum iRobot had ever built. People balked at the price. They called it overkill. Yet, years later, it remains the gold standard for a very specific type of person: the one who hates seeing even a single speck of dust in the corners of their kitchen.
Most round robots are fundamentally flawed. Think about it. You’re trying to clean a square room with a circle. It’s like trying to fit a peg into a hole that doesn't exist. The iRobot Roomba s9+ changed that conversation by adopting the "D" shape, similar to what Neato used for years, but with a level of suction that feels almost personal. It doesn’t just sweep; it hunts.
The Physics of the D-Shape and Why It Actually Matters
Standard robot vacuums have a side brush that tries to "flick" dirt into the path of the suction. It works... okay. But the iRobot Roomba s9+ puts the main rollers right at the front edge. Because the front is flat, those dual rubber brushes—which are 30% wider than the ones on the Roomba i7—get within millimeters of your baseboards.
I’ve seen people complain that the s9+ is "too loud." Well, yeah. It’s moving a lot of air. We’re talking about 40x the suction power of the old 600 series. When it hits a rug, the "Power Boost" kicks in, and it sounds like a small jet engine taking off in your living room. It's annoying if you're trying to watch Netflix, but it’s exactly what you want if you have high-pile carpets that act like a graveyard for allergens.
Corner Dynamics
There’s a specific sensor on the side of the s9+ called the PerfectEdge sensor. It’s a specialized 3D sensor that constantly scans the wall. Instead of just bumping into things blindly, the robot uses this to "hug" the wall. Most robots shy away from corners because they’re afraid of getting stuck. The s9+ dives in. It uses a specially designed five-armed corner brush that spins at a specific RPM to pull debris out without scattering it across the floor like a chaotic weed-whacker.
The Clean Base: A Love-Hate Relationship with Convenience
The "plus" in the name refers to the Clean Base Automatic Dirt Disposal. This was a game-changer. You don't touch the vacuum for 60 days. It returns to the dock, and a secondary vacuum inside the base sucks the dirt out of the robot's bin and into a sealed bag.
It’s loud. Seriously loud. For about 15 seconds, it sounds like a shop-vac is running in your hallway. But for anyone with allergies, this is the holy grail. You aren't emptying a dustbin and breathing in a cloud of dander every afternoon. The bags are AllergenLock, meaning they trap 99% of pollen and mold.
- The Cost of Convenience: You have to buy replacement bags. It’s a recurring cost that some people find irritating.
- The Reliability Factor: Occasionally, if the robot sucks up a literal sock, the base can’t clear it. You'll get a notification on your phone that says "Bin full," and you'll have to play surgeon with a pair of needle-nose pliers.
- The Size: The base isn't small. You need a dedicated spot for it, preferably on a hard surface, with a bit of clearance on either side so the s9+ can find its way home.
Mapping and the Intelligence of iRobot OS
The iRobot Roomba s9+ uses vSLAM (Visual Simultaneous Localization and Mapping). It has a camera pointed at an angle toward the ceiling. It looks for landmarks—the edge of a doorframe, a picture hung on the wall, the corner of a sofa. This is how it knows where it is.
It’s not perfect. If you try to run the vacuum in pitch-black darkness, it’s going to get lost. It needs at least a little bit of light to "see." However, once it creates a "Smart Map," you gain an incredible amount of control. You can draw "Keep Out Zones" around the dog’s water bowl or "Clean Zones" right under the dining room table where the kids drop crumbs.
Why Privacy Advocates Like It
Unlike some cheaper competitors that have been caught in data leaks involving camera images, iRobot has been pretty vocal about their encryption. The images the robot sees stay on the robot. The map sent to the cloud is just a series of lines and coordinates, not a photo of your messy bedroom. For some, that peace of mind justifies the premium price tag.
Real-World Limitations: The "Clog" Factor
No review is honest without talking about the failures. The s9+ is powerful, but it's also low-slung. Because it sits so close to the ground to maximize suction, it can struggle with transitions. If you have those thick, decorative transitions between a hardwood floor and a tiled kitchen, the s9+ might occasionally do a "turtle" maneuver where it gets high-centered and gives up on life.
Also, pet hair. While the dual rubber rollers are "tangle-free," that's a bit of a marketing stretch. Long human hair or thick husky fur will eventually migrate to the axles of the rollers. You still have to flip the thing over once a week and pull the hair out. If you don't, the friction will eventually melt the plastic bearings. It’s a $1,000 machine; you have to maintain it like one.
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The Software Updates
One thing iRobot does better than almost anyone is software support. The s9+ you buy today is actually better than the one that launched years ago. They’ve added features like "Careful Drive," which uses the sensors to avoid bumping into furniture with too much force. It used to be a bit of a battering ram; now it's more of a gentle prober.
Is It Still Worth It in 2026?
We’re seeing a lot of "combo" robots now—machines that vacuum and mop at the same time. The s9+ doesn't mop. It is a specialist. It does one thing, and it does it with more raw power than almost any "Jack-of-all-trades" hybrid on the market. If you have a house full of carpet, a hybrid is a waste of money. You want a specialist.
The iRobot Roomba s9+ is for the person who wants their floors to feel "barefoot clean." You know that feeling when you walk across a hardwood floor and you don't feel a single grain of sand under your heel? That’s what the s9+ delivers. It’s a premium tool for a premium result.
Actionable Maintenance Steps for Owners
- Wipe the Sensors: Every two weeks, take a clean, dry microfiber cloth and wipe the cliff sensors on the bottom and the camera on top. Dust buildup here is the #1 reason robots start acting "drunk."
- Check the Filter: The high-efficiency filter in the bin gets clogged with fine dust. Don't just wait for the app to tell you to change it. Tap it out against the side of a trash can once a week to maintain that 40x suction.
- Rotate the Side Brush: The corner brush will eventually get "legs" that are curled or bent. You can actually dip them in hot water for a minute to help them regain their shape before you spring for a replacement.
- Clear the Charging Contacts: If the robot docks but doesn't charge, there's likely hairspray or dust buildup on the metal contacts. A quick rub with a bit of "magic eraser" or a cloth dipped in rubbing alcohol fixes this instantly.
The s9+ isn't for everyone. It’s loud, it’s expensive, and it requires proprietary bags. But in terms of sheer deep-cleaning capability, especially for corners and carpets, it remains in a league of its own. If you have pets that shed enough to make a second dog every week, this is probably the only robot that can actually keep up.