Hi,
Happy new year !!! Congrats on your purchase!
The way I have achieved what you are trying to do is to set up two registrations - the first with "normal accomp" operating and the second with just the drums operating (same style or different or whatever you want) Then when I want to dive into drum heavies I activate (press) the rego button and bingo (or bongo). To make it more natural (to save going for the buttons) I assign both regos to one of the foot controllers. As part of each rego setup I would assign the foot controller to reg+ for the normal accomp and then reg- for the drums only accomp. This sets up a loop which then allows you to do all soughts of things. You can get smart and chain different drum beat styles together as above (via dif regos)and thus be able to change your mood on the fly.
There is another way which I have not fully explored and that is by assigning one of the controllers to "Percussion". (page 160 in the manual)I will have a play with this option and let you know.
I hope this helps.

Hi Deaton,
As you may have already read from the private email I sent you earlier this evening, I had suggested the same approach as JonPro. The Registration Memory Banks are a powerful tool to customize just about every setting on the 9000pro, including 'which' auto accompaniment parts play (sound) or not.

Congratulations on your new 9000pro

- Scott