Hello, I'm new, I'm French and I don't know how to use archicad very well... A lot for a lonely man.
BUT ! I have a mighty mouse from apple and I'm very proud of it. Unfortunately, I don't manage to use the zoom with the incredible central button (I don't know the word : serrated roller ?)...
I read somewhere that if you install the drivers with the mighty mouse, you loose the scroll/panning function in AC9. I read that you should just use it out of the box and not install the drivers?? Try unistalling.