I think he's probably old enough for an iPod. I would look into starting him off with the Nano. It's smaller in size, capacity, and price. There is one called an iPod Shuffle, I think it's changed a bit, but you used to not be able to pick your songs, etc. So, although that is the cheapest model, I would definitely check into it before buying b/c part of the allure of the iPod is being able to select your stuff! Also, you can do iTunes gift cards (or suggest it to other family members) so he can get a bunch of music right off the bat. The i-products in general are pretty easy to use. I'm no techie myself and I figured it out fairly easily, so just get one of his friends or his uncle to show you how to do it so you can help him with it if necessary.
They have a variety of docking stations to put the iPod on and play music into the room. They range in price and the cheaper ones really are kind of cheap, but it depends on what you need it for. They also sell combo clock radios/docking stations too. I would probably hold off on one of those until you see how often he uses it. Most kids I know that age are perfectly content listening on their headphones and sharing their headphones with their friend.
oh and I wanted to say, don't do a boom box. They really are outdated and by the time you buy the stack of CDs he'll want you might as well have just bought the iPod. Besides, on iTunes you can buy just one or two songs and not the whole album.