Should have gone for broke and killed them all.
Perhaps he did. Seems like he hit a second person, who managed to get away with his friends.
If they were running away, that could get the homeowner a murder charge. It depends on the Prosecutor.
Authorities really don't want people to resist criminals with force. The "right to self-defense' really does not matter to them.
The police who arrive are nobody's friend. They are there to arrest somebody if they can.
The first to arrive on a home invasion call always assume they may be dealing with a drug dealer or drug warehouse robbery. They will be wary and suspicious. Even if they determine that is not the case, they may still have an unfavorable attitude about the homeowner.
The best thing to do in the aftermath is to shut up and wait for your lawyer to arrive. The police will take your weapon for "evidence" and you won't get it back for months - if ever. Give it up without argument. Get another one later.
If detained, just wait for your lawyer to do all the talking. Do not argue or speak with the police. You do not know what utterances will turn a detention into an arrest and charges.
"The only winning move is not to play". (Wargames, 1983)