Are you creeping on your crush?
I can totally see why you’re feeling a little bit weird about the situation. Having access to so much info about one person does have the tendency to do that. Keep in mind, though, that plugging into all of someone’s social media profiles has become the new norm. What you see as stalker-ish, he—and lots of other people—probably just sees as a standard way of keeping in touch.
That being said, he is your crush. Try and communicate with him. If you see he’s on Facebook at the same time you are, send him a quick message. Or maybe shoot him a text when something funny happens that you know he’ll appreciate. But only text him if he personally gave you his number. Otherwise, yeah, it will look kinda creepy.