If you are referring to fglrx, I'd guess a resounding no.
From my experiences the newest driver doesn't even build in fedora 8, and when you tinker with it to get it to work it causes every gl application to segfault. Way to go guys, great product!
But Fedora 9 is currently alpha, so it is running a lot of new/testing stuff. It is running the recently released 2.6.24 kernel & a development version of x.org so I'd guess fglrx will support that... sometime in Q3/Q4. Fortunately by then the open source alternatives should have 3d working (at least rudimentary, which is still better than segfaults).
In fact if you are lucky, fglrx will support f8 by April when f9 comes out, and then f9 when f10 comes out.
Im currently using fglrx drivers compiled from atis site, remember that you need kernel-devel package to make driver modules.
And also if you want you could use livna repo for easier fedora 6-9 driver install. http://rpm.livna.org/rlowiki/ for 6-8 and if you want to use fedora 9 packages just search net how to use its "development" repo.
Sorry guys, but I kinda lost in what you saying. I'm successfully using ati 8.4 drivers on Fedora 8 and haven't had any problems for months. My question was if those drivers, or latest 8.5, would install and kernel modules compile on FC9. I'd like to upgrade my system, but just have to know if graphics card will work.
I wish I knew if this were something someone might be able to patch, which I could hold out for with a single monitor, or if it will require a new ATI release, and I should just downgrade my X-Server to the Fedora 8 one (PITA!).
Maybe I should send the radeon devs another monitor or some beer or something as encouragement to make dual head work