Here is what you need to install it properly and have everything work as it should.....
http://chrisb.users.superford.org/Mazda_CX-9/Projects/Stereo/Stereo_Upgrade.html
Been tied up for the past 6 months, so haven't done much to the 9, but.....
In late April had the master cylinder replaced. Then in late May had the ABS module & left outer tie rod replaced, brake fluid flushed & 4 wheel alignment done.
Good like new'ish. 👍