Sounds like me, growing up. I was diagnosed with AS as an adult, which explained a lot.
However, my mom set one ground rule...no reading at the table. If you set a rule that he cannot read at the table, and then share all three meals with him sitting down (and make a nice meal that will take a bit to get through) you've got a few hours guaranteed with him. He's 9...
...and if I were you, I would be SOOOOO thankful this is how he wants to spend his time!! I turned out okay, and I LOVE to read, still. :) Of course, as an adult with two children, I don't have that kind of time anymore, but I wish I did.
As he gets older, he'll learn to moderate. In the meantime, realize he is in the GOLDEN YEARS for reading...where the books are the most exciting, etc. Please don't ever take it away as punishment, and try to realize how fortunate you really are.
***Oh, and btw, I devoured comic books as well as regular books, and I'm serious. I have a collection of over a 1000 comics, and now they're worth a lot of money, and I'm saving them for my children. Depending on what comics he's reading, they can be educational, but if that's ALL he's reading, you need to get him to books.