If a guy likes a girl he will talk to her.
Having said that the next time you see him you can introduce yourself by first name and say something along the lines: "Hi I'm Jazzy. Awhile back I (thought) I saw you on a bus that my uncle drives. Did you move in the area recently?"
If he responds with just a simple yes or no and looks away then odds are he is not interested in you. If he tells you his name or elaborates on why he was on that bus or tells you that he did indeed move with a smile on his face or in the tone of his voice it's a sign that he is glad you broke the ice.
At any rate from then on whenever you bump into one another your can casually greet each other by name and from time to time chit chat about some upcoming school activity and then move on. Again if he's "half way interested in you" he will initiate conversations now that you have introduced yourself to him and welcomed him to the new neighborhood. The best way to avoid appearing to be a stalker is for you to treat him like he was just anyone else. In fact it wouldn't hurt for you to seem too busy to talk long or be seen talking with other guys or hanging out friends.
Last but not least you have to be prepared to accept the fact sometimes people you have crushes on will not be attracted to you. He may already have a girlfriend or he is gay. That's just life!
Nevertheless one is better off (knowing) where they stand than to be left wondering "what if?"