It sounds like a very good EC for him given his high level of performance. He won’t be sorry later in life, either (whereas sometimes I would like all of those hours spent practicing my clarinet back to put my ‘10,000’ hours into something else!). I probably would encourage him to do a couple of other things – maybe a consistent volunteer activity/area through the next couple of years, and SOMETHING in the summers besides debate camp. 
Model UN, speech, etc. could be good additions, and sort of related but not exactly the same.