Took my car in to have the mirrors looked at. Dealer said there was not a TSB but there was some other document that said to put foam tape under the mount where the mirror housing swivels.
This resulted in absolutely no improvement on the vibration issue. I called the dealer soon after leaving the parking lot to tell them there was no improvement. Service advisor talked to Mazda tech support and came back with "Some vibration is normal" Recommended I drive another car on the lot to see if they vibrate the same. I don't really care if they all do, it is unacceptable and clearly a design issue or else all cars would have this same issue.
I've never owned a car where the mirrors vibrated. I was driving home in our VW Jetta over some bumpy rodes and noticed no vibration at all. When I got home, I lightly tapped the Jetta mirrors and there was no noticeable movement. Same tap on the Mazda CX-9 mirrors caused the mirror to vibrate.
Out of curiosity, for those of you who notice the vibration issue, do you also see 60hz flicker in computer CRT monitors? This drives me nuts, I can't work at a monitor that flickers or even be in someone office where it is flickering. I always reset the refresh rate to something above 75hz.
I am logging all my phone calls and trips to the dealer on this one. I have a hunch that MAZDA will eventually have to fix this problem.