since you didn't say what body you'll use, I'll give you the standard settings using my 7D for indoor basketball. Set shutter to 1/640, your 85mm f/1.8 to f/2 and raise ISO setting until you have proper exposure. Standard HS gyms are around ISO 2500. If the venue is particularly well-lit for you, you may want to sacrifice ISO for 1/800 on the shutter for the quicker college players.
Shoot in manual, don't choose any of the auto settings. Put camera in centerpoint only focus mode. As for WB, if you can't do some sort of custom WB, choose the fluorescent setting which is usually closest to reality in a gym. As someone mentioned, try to meter some shots with the players on the court during shoot-around prior to the game.
If you have court side access, a great place to setup with the 85mm lens is on the sideline and about 5' behind the baseline. From this vantage point, you'll be able to get full bodies in shots around the basket. Also, anything on your side of the court from the 3pt line to the foul line will be good also.
Last tip: Setup your camera for good exposure and enough shutter speed then don't mess with things. Lighting is usually fairly consistent on basketball courts. There are some dark(er) zones, but that's the way it is. Set it, forget it and concentrate on shooting the game action and not messing with your camera setup.
Good luck and be sure to post some shots.