Wow, bad judgement all around though the guy with the firearm takes the prize.
Juveniles with bad judgement are par for the course, and I have no doubt that what they were up to was threatening to Wyatt Earp there.
On the other hand, to legally discharge his firearm Mr. Earp needed to be in immediate jeopardy for his life which he clearly wasn't. His 'going for the tire' make that even more clear.
What exactly is the requirement to get a CCW permit in this neck of the woods? Judgement and knowing the law seem not to factor into it.