Do you need to have attended a service academy or an ROTC program to become a CRO?
No, you do not need to do those. You can go to OTS after getting your degree and go CRO.
I am not currently in any college program for AF ROTC but if I finish my degree and then want to go Combat Rescue officer, would that be that same as PJ training?
You will go through all of the same courses except for paramedic school. When you are in OTS you will need to complete a phase 1 package. Then go to phase 2 where you will be put through a selection process.