That is wonderful news that he is well enough to be home with you!
You cannot beat yourself up over it. It is not like you were being careless. Accidents happen. I have had things happen to me that totally scared the beegeebees out of me...I shut a door on one of my pups one day. Thankfully, she was ok...I think I was more traumatized than she was. I cried all of the way to the vet. She was fine. Things can happen in an instant and anyone who says otherwise is lying. What a terribly frightening thing to go through. Now, if you said that you put him up on an 8 foot ledge and left him and he jumped off and got hurt....I don't call those things accidents. Ya know?
Give him lots of belly rubs and tell him lots of people wish him a speedy and complete recovery!