@Hatchet_Jack there are a lot of good ideas here. A lot of it will come down to personal preferences of you and your son. My youngest is 10 and got a SAK Tinker for Christmas when he was 6, along with a couple bars of soap for carving and some extra band-aides. Now might be a good time to teach some basic first aid skills for minor cuts. We've definitely had a few.
All three of our kids use their knives regularly, but they don't really carry them around. Kids are at school most of the day anyway. Also, my wife and I designated a "home" for our kids pocket knives (ok, it's just a spot in our kitchen knife drawer). That way the kids always know where to find their knife when they need it, and where to put it away. They haven't lost any knives yet.
My son loves that Tinker and thinks all of the tools (that don't really get used) are super cool. On the other hand, he also has a Case peanut that probably gets more use. The small blade on the Tinker as well as the peanut are great for carving.