Woodies is a good place to learn, probably better than the river. The waves are pretty small... The river has very small beaches, with trees, powerlines and roads waiting to snare you. Also the wind is much gustier on the river.
Advice for Point Walter - lots of sharp rocks if you walk out too close to the shore. Go down the sandbar a bit and downwind of the other kiters. Don't miss the end of the sandbar though!
You could also try Melville Beach in Applecross in a SW. Start downwind of the big gum tree.
Check out the WAKSA website also
www.waksa.org.au/locations/