Okay so this guy asked for my Kik and I gave it to him and we've been flirting but he stopped replying to my texts 2 days ago and we're supposed to be going to the movies on Friday. So did he change his mind?

Only way to know really is to ask him yourself. Maybe don't ask it in a way that makes it seem like you're worried or whatever.. Something like "hey are we still on for Friday?" Or "what movie are we watching Friday?"or even suggest which movie you'd like to watch.. If he still doesn't reply, something might be up.

You can't assume it's that he's not interested straight away: He could have no credit on his phone or maybe he's been arrested?