Heh. Not to worry. Speaking as a middle- and high-school teacher, I'm quite familiar with how the adolescent mind works (or doesn't, usually). "Techno" for an 11-year-old is usually something you'd hear on a mainstream pop radio station (you know, the ones that give away free tickets to Mariah Carey concerts), but maybe with a little more synth to make it "edgy."
To wit... one of my students (a freshman, so not too much older than your boy) came up to me the other day, waving her iPod in my face, and saying animatedly, "You've got to listen to this weird music I got from an online friend lastnight!"
I asked her what was weird about it and she said, "It's called..." (and here she crinkled up her nose, trying to remember the weird name for the weird genre) "...ska, I think?"
I just about fell over laughing.
In other words, their sense of music is pretty limited. So what they call "techno" or "ska, I think?" is probably only some cheap imitation of the real McCoy.
That said, I wouldn't discourage you from nudging certain albums his way, just to be on the safe side.