Hi there,
I did in my CX-9 2016, it was working with my Android 6 but after the most recent service with the authorized dealer they uploaded the most recent version and the hack is not working now, I have to install it again and verify if it is working.
I located this in my local mercadolibre.com.mx non-official seller. Activates mirror screen, includes Pause in the mute when have ipod or USB music, includes an option to run movies from an USB pen drive and includes the Speedometer app.
It does the screen mirror for only 60 minutes, after that you need to connect it again but need to restart the phone and turn off the car. for short trips -less than 1 hour- it's useful.
Nice if you want to see in the main screen Waze, gps or favorite movie for your kids.
Although I do not like screen mirror function because everything must be managed from your smarthphone, cannot control from the headunit. For music I use my Ipod Classic 160 gb, 'cause with my smarthphone takes a lot to charge my 36gb of music I have in in my microSD card and everytime I connect it starts everything again, useless.
I have heard it is the same for Mazda 3 than CX-9
Saludos