I think on the older CX9's like yours you have to replace the entire head unit to get the OEM backup camera. It would be alot cheaper just to get an aftermarket one.
When I got my 2010, I had two options.. if you got the bose radio, then the display in the center console was shared between the radio and backup camera. If you got the standard audio and wanted a rearview camera, then the display was in the rearview mirror.
After five years of ownership, I rarely remember to look at the backup camera because its down in the center console, and I'm looking up at the rearview mirror while backing up. I can see how having the backup camera display in the rearview mirror may be beneficial.
