How do I attract him without scaring him off?

You basically just described me in high school. I've always been very outgoing, and flirtatious. In school I got along with everyone, and was constantly passing notes with girls in classes. I had absolutely no problems whatsoever talking to girls, that is, until it was a girl I liked. For some reason if I really liked the girl I would just clam up whenever she was around, which was so uncharacteristic of me. I didn't appear shy because I was very outgoing in every aspect concerning social interactions, but that's exactly what it was, if I liked her - I got shy. I think it may have been a fear of rejection, I'm not entirely sure, I'm no shrink. It does sound like he likes you, if you like him too you're probably going to have to make the first move, or, you're going to have to make it extremely easy for him to make the first move. Either way, it does sound like he has a crush on you. Ask him for help with homework, or a school project. Ask if he's going to a school event, ask if you'll see him there. If you're interested you're probably going to have to start the conversations, at least until his heart quits beating in his throat.

He's shy! that's is soo cute.
find some way to make small talk. Like the whole dropping your pencil thing. Usually works. Unless he is simply oblivious, which I doubt cause you said he no problem with flirting.
ask him about something he likes and/or is passionate about. Like a sport or a hobby. That will get a conversation going.