94’ S10 Blazer, CD player won't turn on

You didn't mention checking the ground.  Also wouldn't hurt to check the battery connections even though you have measured power on the wires, and check frame ground as well.  And sometimes a stereo has a fuse on the back of it either inline on the power wire(s) or on the chassis itself.  Check it.

And I agree with DYohn, the stereo might have taken internal damage that cannot be seen.

You can remove it from the dash, then splice main power and constant power together(usually red and yellow wires) and then hook it straight to the battery with power wires on positive side, and ground wire on negative side.  Then see if if will come on.  Have a friend to help hold the wires while you turn it on.

Good to hear you are OK, and you are right you WERE LUCKY.  You should thank God for Him sparing your life.  He was watching over you that day.  I've been in several accidents including driving in a 93 Corsica that was hit in the side by a semi tractor trailer driving up the wrong side of the road as I was making a left turn into a gas station.  He came from behind me and I didn't see him cause I was looking ahead at the oncoming traffic.  I never imagined that a semi would be coming the wrong way and hit me.  I was lucky too.  No one was hurt.