We spent nearly six months in Colonial Williamsburg last year, doing research for several writing projects. I think we did just about every single evening program.
Pirates Among Us (and its sister, Ghosts Among Us) are absolutely perfect for your DS, unless he has any particular fears unusual for his age group. For both programs, you'll meet up with your tour guide for a short introduction. Then your guide will lead you inside several of the Colonial homes/buildings. In each location, your guide will give you a bit of factual nuts and bolts (so and so was convicted of piracy in 1747 because he did X, and he was executed on blah blah date). Then you'll watch a scene performed by a member of the acting troupe, taking on the role of that pirate (or ghost).
It's atmospherically spooky...the rooms are lit by candles and the actors are first-rate, drawing you into the scene. But it's not scary scary--nothing jumps out at you, you're clearly sitting in the audience watching a scene, and it's easy enough to step out of the room if he does get scared. There were a few VERY young kids (under 5) on our Pirates tour...most got scared at some point and had to be taken out, one was just noisy and constantly disruptive. But the kids your son's age LOVED it.
Other good evening programs:
Cry Witch--sit on the jury for a witch trial...my favorite since I was that age
Crime and Punishment -- participate in a military tribunal, asking questions to determine whether a military officer acted appropriately. If he's into history and military stuff, he'll LOVE this, otherwise it might go slightly over his head.
ANY of the Murdock shows. I'm not sure what'll be playing while you're there, but my personal favorite is The Great Theatrical Disaster of 1790...farce at its finest. Polly Honeycombe, Murdock's Miniature Medley--basically, if it has the name Murdock in the title or website description, it's a super-funny 18th century play starring the professional acting troupe. The reenactors are fantastic, but the professional actors are even better.
You'll have a wonderful time whatever you decide! I absolutely love Colonial Williamsburg! Make sure you eat at the taverns...stop by Chowning's after 9 p.m. if you have a late tour. Your son will love the Colonial games and music!!
If you have any other questions, feel free to ask!