Of course that's what's cool about the 9000Pro is that you can add polyphony: the piano expansion alone adds a respectable 64 notes to just acoustic piano thus leaving the full 128 notes of the keyboard for other things. Or you can turn that around and use the keyboard as a drawback organ simulator and use an XG expansion card with 32 notes of polphony for backing. How much polyphony you actually need depends on the number of instruments in your accompaniment or backing and your live playing style.

It's possible, just maybe, that the added memory of the Tyros means that more memory has gone into voice production and the organ drawbars don't take one-note-per-flute. We won't know until somebody makes a point of trying the Tyros simulated drawbar organ with accompaniment. But if Yamaha maintains the same scheme with the Tyros that it used with the 9000 Pro for organ flutes with no way to expand on the polyphony, then organists are screwed.