yes this guide works for rehat9.
the only things that changed are the kernelpatches.
use kernel 2.4.20 with the latest stable patch 2.4.21.rc6
you dont need the agp-patch.diff used in this guide. i think these patches are needless with actual kernel/kernel patches.
also: the updates for rpmbuild and grub are needless. these versions come with your redhat distro.
for the nvidia graphics driver i used the nvidia_xyzXXXX.run script from nvidias site.
this script just did it fine for me.
for alsa i just can say: RTFM!