Just kidding. I had a CX-9 for four years - - just traded it in on a Mazda5 (also three rows). I wanted something smaller.
First off, I think the 2008-2011 CX-9 models are rated at 273HP.
Second, have you actually DRIVEN a CX-9? If you have and it doesn't meet your performance expectations, fine. If you haven't, I urge you to test drive a new CX-9 to see for yourself...you may be surprised.
If you find the performance is lacking, about your only realistic option is a used Acura MDX with 300 HP. The CX-9 is good for 0-60 in about 7.5 seconds, while a used MDX might break seven seconds. Otherwise, you're going to pay a LOT for appreciably better acceleration from an SUV/CUV with a third row of seats. One exception might be the new 2011 Dodge Durango with a Hemi engine. You might get a deal on one.
As far as turbocharging a CX-9, I would advise against it. First, there are no "kits" made for the CX-9 - - you'd be paying a premium for a custom installation. Second, you would void any drivetrain warranty remaining on the vehicle. Third, when you go to sell your CX-9, the typical family in the market for one will not be interested in having a modified, non-warranty engine.
Like I said, you're crazy (but I like your train of thought).