Guys,
FWIW I have drive a 2009 MS3. The OEM intake system on that car is restrictive, has been proven so, and it's a performance car, not a family hauling grocery gitter. Most everyone who owns one and wants to start modifying it to make a bit more power starts with the intake system because so much noticeable power is available easily. That and a quick tune with a Hypertech or COBB will make a huge difference in the performance of the car. I know as I'm running both on mine. Just saying not all OEM systems - even from Mazda - are great off the showroom floor.
That said, until somebody conclusively proves the OEM intake on the CX9 is restricting the motor and costing HP, I don't see any point in buying a CAI for it unless you like wasting money. I also own a 2010 CX9 and have considered tinkering with this briefly.
There are multiple ways to go about this, but seeing as the demographic for the CX9 isn't going to be overly interested in spending $250 or more to gain 5hp that they'll only see at 6000rpm anyway, I highly doubt you'll see anyone bother. To top it off, even though this engine is utilized in the Edge, Taurus, and Mustang, I believe they use a different ECU, tune and intake system. So even if somebody unveils hidden HP in the 3.7 Ford engine by way of tuning and exhaust that justifies letting more air into the motor with an intake in those cars, it won't likely apply to ours. Even if it did, I would expect the cost to be nowhere near worth the gains.
Finally - my opinion here - Weapon R products are garbage! Had one for a Maxima. Filters are foam style and restrictive junk. I'll never buy anything from them again. They found a way to throw something together for the CX-9 and take a few people if you ask me. I would love for somebody to post a dyno sheet proving me wrong but I am not holding my breath.
Two cents provided - thanks for reading.