For me, the current kernel brings it:
[root@trabant ~]$ rpm -qf /lib/modules/2.6.18-308.1.1.el5/kernel/drivers/net/wireless/ath/ath9k
kernel-2.6.18-308.1.1.el5.x86_64
And the modules are there - hopefully this helps:
[root@trabant ~]$ lsmod | grep ath9k
ath9k 299637 0
mac80211 183105 1 ath9k
ath 43585 1 ath9k
cfg80211 189961 3 ath9k,mac80211,ath
Running ifconfig shows (wlan relevant only):
[root@trabant ~]$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:16
3:....etc
inet addr:128.xxx.xxx.xxx Bcast:128.194.136.255 Mask:255.255.255.0
inet6 addr: fe80::216:d3ff:feb5:d70e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5160442 errors:0 dropped:0 overruns:0 frame:0
TX packets:731414 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:7440528412 (6.9 GiB) TX bytes:75471919 (71.9 MiB)
Interrupt:201 Memory:ee000000-ee020000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:4291 errors:0 dropped:0 overruns:0 frame:0
TX packets:4291 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4617396 (4.4 MiB) TX bytes:4617396 (4.4 MiB)
sit0 Link encap:IPv6-in-IPv4
NOARP MTU:1480 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
wlan0 Link encap:Ethernet HWaddr 00:19:7E:48:etc....
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
(I'm on Scientific Linux 5.8/64)