Lake or stream?! What is the skill level of everyone?
There are some stocked ponds around that might be ok (presuming that the 9 y/o is relatively unskilled, but I could be wrong)...
Grotto, Spruce Meadows (if there isn;t an event on) sibbald, the pond in Cochrane, etc. Upper K, maybe?
There is always the bow (in and south of Calgary)!!