He deserves at least a manslaughter charge.
I think there is a lot more to this story than is contained in the newspaper article.
If the homeowner's actions were as bad as the paper and some posters here make them out to be, the police would have arrested him already. Especially, since it happened in Palm Beach, which is one of the most liberal parts of the state.
I would guess that either the homeowner did an excellent job of convincing the police that the perp did something to cause him to fear for his life, or was committing a forcible felony. Or that the police had many run-ins with the "good kid", and knew that he was trouble. Or both.