You should note you can get off of all Citybus 962's on the Kowloon side as well, at MTR Kowloon Station in about 30 mins. then a minibus to TST or walk in about 15-20 mins. Or take KMB 52X from Aegean Coast to Cheung Sha Wan in Kowloon in about 35 mins. then a bus onward to TST (there are lots!). And I think Mat was referring to 962N as the night bus, since 962X runs on Tuen Mun Road and won't come close to Aegean Coast.
Light Rail will not get you to Kowloon....it is a rail system for Tuen Mun, Yuen Long and Tin Shui Wai only. It is very slow (you can run faster than the train often!)
KCR West Rail from Tuen Mun is slower than MTR, and it swings north into the NT first so it may be slower overall than bus. And it doesn't link up with East Rail to TST, so you have to get off in Mei Foo and switch to MTR/bus or Nam Cheong and again switch to bus to get to TST.
I'd avoid the whole hassle and stick with the bus. If you luck out and get a F1 racer wannabe for a driver, its alot faster than KCR.
Check out www.ypmap.com, www.citybus.com.hk, and www.kmb.com.hk for more detailed routes and approx. times.