Firewall can't stop it his using a weak booter thats why. He can tell where you live etc because he put your IP in google > IP lookup or tracer no worries about it though he can't do anything just a little random kid excited over a booter his used for his 1st time.
I advise to reset your router/modem and check if your IP changes. Don't leave it otherwise your IP will remain the same and you may not be able to sign in. If you restarted your router/modem and your IP didn't change phone your internet provider they will change it for you and maybe upgrade your router for a small fee to a dynamic router.

This guy on PSN has threatened to ip flood me, is there any way I can prevent this from happening? Would I be able to obtain his ip if he does flood me so I can flood him back with a booter or something?

So pretty much my firewall is pretty good and his booter is bad? I should fine right?

You can DDos anyones internet no matter what firewall they have it all depends if there booter is strong enough to kick your home connection offline which most of the times they are thats why its important to have an dynamic ip so you can change your IP right away. But I think your fine just block the kid and stay away from people who ddos people offline cause your most likely gonna end up getting attacked too.

If he floods you, just call your ISP and they will block his IP. :p

One he changes his ip he can ddos anyone again, it don't help blocking ip's you need a dynamic ip so you can just change your ip.

So his booter is to weak to actually kick me off the internet, only make me lag a bit?

I believe I have a dynamic ip. How can I find out?

Check your current ip google > whats my IP ..... .... ....
Once you see your IP go to your router downstairs or where ever you placed it and click the reset button once it loads back up check your ip see if they changed if it did you have an dynamic ip which is good. If it did'nt then your kind of screwed aka static ip.
Im off to sleep bro hope i helped.