The short answer is 3123 wont work in RedHat 9. If you compile a custom kernel from kernel.org, sans redhat patches, then you can build 3123. But then GLX will be broken anyway.
So I have RedHat 9, Linux 2.4.21-pre7, and NVIDIA 1.0-3123 with no OpenGL support. The only reason why I don't just use the open source nv driver is because I need DVI and TwinView support.
Waiting patiently for the day that I can have openGL, twinview, and an uptime of > 1 hour.