Hi, Belle!
I'm not sure, but I think that Cub Scouts has firm rules about being either a certain age or a certain grade level for each level of scouts. So, Tigers might be the right group to join from that perspective.
However, besides the arts and crafts part, each month or so the boys are supposed to go on a "Go See It." This is often hiking in a nature area, visiting a fire station, visiting a local factory, etc. So, he could really delve more deeply into these things if they interested him. And don't forget that each scout participates in both the Pinewood Derby, where they get to design their own car, and the Raingutter Regatta, where they get to design their own boat to race. Those end up being anywhere from simple projects to as advanced as your scout wants to take them. They're fun and, at least where we live, the younger boys can compete against the older boys. It's a fun, safe way to learn to handle competition, and victory and defeat besides.
Also, once a month, the entire Pack (all-grade-level Cub Scouts) gets together at the Pack meeting to get awards and play games and sing songs.
Oh, and also, in the Tiger Scout Handbook you'll find all kinds of optional indoor and outdoor activities that are fun to do, and once your son gets his Tiger badge, most of those activities will earn him belt loops. And since you do them at home with your son, you can adjust them to his level of learning and fun.
HTH!
