[redgolum]

If you had a CCW, and shot the kid in the same situation, would you be charged?

[caseinpoint]

No. As a private citizen as opposed to a cop who is entitled to a presumption of authority to stop and order people around, I would have no right to create a dangerous situation by stopping the vehicle in the first place. I can’t see such a shooting justified except in circumstances not present in this case..

[zeugma]

If you had a CCW, and shot the kid in the same situation, would you be charged?

Yes, because you weren't wearing a magical blue suit that absolves you of responsibility.