"what are some of the reasons why I should upgrade to Fedora other that Redhat 9.0 is no longer supported?"
Red Hat does not support Fedora either. Fedora is the free, bleeding edge, unsupported version of Red Hat.
"Does fedora use a newer version of the kernel (like 2.6)?"
Here is a list of what Fedora contains.
"I've heard the current release of fedora messes up your GUI when you bootup, whats that all about?"
I never had that problem.
"Maybe I should wait till they debug/fine tune Fedora before upgrading or is it suitable to download the 3 .ISO's and performing an "upgrade" so I can preserve my current configuration?"
Upgrading in place on top of an existing system is asking for trouble. Instead you should install any new system in its own partition(s) and dual boot. After you get Fedora stable then you can copy over your data and erase your old system.
Be prepared. Create a LifeBoat CD.