I disagree with them. Dont go chopping up your car to mount this. If you had a crappy car it would be different. An 09 is only 3 years old, keep that in mind. If you use double sided tape or velcro to mount it somewhere, make sure its not TOO strong because when you pull it off it takes some of the material with it.
I looked your car up online.. it looks like theres a small pocket under your gear selector. BUT, I dont know if thats easily replaceable or not. Im mounting mine in the pocket under my radio since I dont use it, and that pocket is very easily replaceable for about 5$.