Hey, I know you posted that it's legal to physically punish your kids in Missouri, but you need to know that pretty much anyone at CPS is going to disagree with law and they will still do whatever they can to help you.

This is up to you to navigate. You're nearly an adult, but if I were you I would talk to some of your closest friends (non-mormon if you have any) and share the experience with their parents and ask if you can stay with them if anything ever happens again. If anything does, then at least you have a plan to get out and get somewhere safe. And if they're really cool they'll let you stay with them until you graduate and can move onto college or to your own place or whatever.

Your dad now knows he's on someone's radar (CPS and police). Hopefully he's the sort of person who will take this as a reality check, but if he's an asshole he'll try to find ways to get even with you. Don't let him take your autonomy or freedom away. Do not let him threaten you, especially not physically. Be a good kid and follow the house rules. Stay respectful. But be ready to leave if things get toxic or otherwise unhealthy.