vst? not that i believe....
Synapse Orion Platinum has a very cool little module in there called the XR-909 that sounds amazing for software. Quite frankly i was more willing to buy that program rather than buy my real TR-909, but too bad Orion only worked on a windows platform and im on a G5...
anyways, you can give that a shot, or just download some samples of them lying around on the internet. If you are a huge freak about quality and are willing to pay up the arse for a sample CD, then you can visit this link and get ripped off, but be happy knowing that they probably took a good time getting you the most out of the 909 as possible....
http://www.bigfishaudio.com/4DCGI/detail.html?515