Would it be possible to file a restraining order..?

Make sure you talk to your parents about it as well. They may have different ideas on how to handle the situation. A restraining order seems a bit harsh at the moment, but his parents should also be made aware. Have you told him DIRECTLY that you're not interested? Oftentimes people just beat around the bush and want the other person to pick on their hints. Before you get a restraining order you should tell him POINT BLANK that you don't want him. But if he continues to creep you out, then a talking to school administrators and counselors may work. If the administrators don't work, then you should look at a restraining order.