Make it fun.
Ton of energy but also a good way to burn a kid out from training.
I'd go with something Danny John style. Simple fun and very effective.
Move big stuff throw big stuff. Basic GPP style stuff.
At 10 years old it doesnt need to be complicated, your body is a growing machine. Make it something the kid enjoys doing and works on overall developement.
Hell, I can just imagine being 10 and getting psyched about strong man style stuff. Anything where it can be a group event between father and son.
Hell when I was 10 my dad bought a basketball hoop and we would just go out and play knockout. It was great overall exercise for both of us and by far some of the most memorable father/son events of my childhood. It doesn't have to involve goals or aesthetics... look at it as a way to build a tradition that keeps your relationship going.
We still play to this day when I get back from college and even though the torch has been passed and he is a good 40 years older than me it is still something I look forward too.