The above answer is a good one, I would add that for any type of contact sport, racquet sport and all activities that involve trauma to eye athletic type safety glasses should be worn.
Any low risk sports is very positive for your son.
However the myopic eye is more sensitive than other eyes to injuries. So for example boxing is no go. Ball games could be dangerous too.
Outdoor activity seems to have a limiting influence on the progression of myopia. So get him out of the house to hike or run or bike or whatever he likes to do.