I just noticed the poster of the solar system on the wall, in Corey Haim's character's bedroom. I had that exact same poster on my bedroom wall, when I was a kid! I also had a jet-powered super-wheelchair with cool red flames painted on the sides, so that was fun too. (My last statement is significantly less accurate than my first statement). Anyway, you can see the poster when he sits on his bed after crawling through his window, right after getting home after he hits the werewolf in the eye with the firework/rocket thing. Here's the poster:
https://www.pinterest.com/pin/622622717205625825/