I have been using the OS X 10.10 beta and tested VMWare Fusion v6.0.4 on a late 2009MBP with XP.
We plan on upgrading machines to 10.10 once it has been released and possibly upgrading to Windows 9 later.
The only issue was that I had to re-enter my wi-fi password in Fuze/Settings/Network Adapter (clicked on WiFi and entered password).
Works!