Maybe not directly call him but be somewhere that he is. For example, if you know he works at the movie theater at the concession stand, go buy popcorn from him and be like, "Hey, didn't you go to my school? I haven't seen you in a while, did you transfer?" If he likes you, he will be flattered that you noticed that he was gone. If he doesn't like you, you won't get much of an answer and move on! Have fun! Yes you should definatly contact him.