i dont know the exact answer to that, but usually the stable releases attempt to actually be stable. so im guessing no. changing to multiple desktops will probably have a ton of interesting problems as it is. gnome 3 on initial release will probably be very buggy in the begining, to put it nicely. again i dont know, but i am guessing 9.1 may have it.
ive actually been meaning to get the 9.0 alpha installed to get caught up on some of the up coming changes. i'll try to do that in the next week or so