In my rehearsal room I use a VP770 (with sustain pedal for piano) to control my BK7m. I also have a FC-7 (foot controller) plugged directly in to the BK7m. I use the BK7m mostly as a drum machine for practicing and for rehearsal when we don't have a drummer. The VP770 sits on top of my organ (KeyB duo MK111). This combo works very well once properly tweaked. Midi implementation on most Roland products of similar vintage seem to work well together, so I suspect that the VR09 will work very nicely as a controller. I strongly suggest that you (also) get a foot controller similar to the FC-7 which is now discontinued. Here is a link to a site that has a 'workaround' solution.

https://roxys.com/shop/roland-fc7-foot-controller/

Like GJ, I also like the BK7m (except for the local controls) and especially (the sound of) their drum kits (Meh on the drum patterns--average, not as good as Korg's - JMO).

Have fun.

chas