The quick way:
pciconf -lv |grep -B3 network
The B is for before, so it prints the three lines above. This shows me (on a Zenbook UX31E, the earliest one, I think) that it sees the AR9485 card. A cursory google indicates that it's not yet in head, though some people have been playing with it. I don't have the links immediately available, but I did glance at it today. So, it sees the card, but (just playing around with a live image), wasn't able to use it. (For anyone who comes across this, the 9.2-RC2 version does work out of the box with the included USB to Ethernet dongle that ships with the UX31E).
Also, when answering
@tingo's request, put in all the output from
pciconf, showing the card, chip and revision (rev). My machine is probably different than yours, but, as an example, my output included class, card, chip, rev, hdr, and all that may be useful.
EDIT:
https://wiki.freebsd.org/dev/ath_hal(4)/AR9300 indicates that you might need to be using CURRENT. Looking at the link that you posted, there's a link on the right, indicating that one should see the link that I have above.
[Further Edit]
Ok, I got curious and downloaded a USB image of CURRENT. I ran it as a live CD and it detected the AR9485 wireless card without problem.