>I'm currently using VFP8 SP1 and VFP 6. I would like to start converting my apps to VFP 9. Can I just purchase the VFP 9 Upgrade or do I need the full version? If I upgrade, will I still be able to use VFP 8?

Yes you are eligible for upgrade to VFP9. Yes you can continue to use VFP8 after installing VFP9.