Welcome to LQ.
Don't know if you can find a flahplayer plugin old enough
to be used in RH 9. The OS was declared dead, obsolete
5 years ago, and is insecure to use 7 years after release.
The current Desktop version is Redhat Fedora 11.
Redhat Fedora 1 was released in 2004.
You are just eleven releases behind.
The current free versions, long term supported,
of Redhat Enterprise EL5 are CentOS 5.3 , and
Scientific Linux SL 5.3.
Anyway, old flash is here
... The earliest versions are for Windows only.
And ... you can't change Glibc. Glibc is