I am an attorney and there are a lot of issues. This is going to be REALLY rough because to adequately answer these questions would take a lot longer than I could write here and it's not worth the effort to give a law school exam answer.....But basically:
1. Reckless endangerment is a criminal offense, not civil. So no, OM could not sue for this. Could Tennessee authorities charge someone with these crimes.....well assuming Tennessee authorities would want to charge people with the crime of "reckless endangerment," the answer would still likely be no because that charge needs to show beyond a reasonable doubt conduct that engages in "imminent danger of death" or "serious bodily injury." Serious bodily injury basically means substantial risk of death, prolonged unconsciousness, obvious disfigurement, loss of a body part/organ, etc. So no, it is extraordinarily unlikely that anyone would bring these charges, not least of which is identifying the actual defendant to charge with those crimes.
2. Kiffin, no. Again see above #1. But also because there is concrete video evidence of the golf ball not hitting Kiffin. It lands on the ground near him and he picks it up.
But, in Kiffin's sake, let's assume he wants to sue for civil assault under the theory of "reasonable fear of imminent bodily injury" (battery would be off the table because he was not actually touched). To say nothing of the legal defects and the meeting of statutory requirements, you'd still have to find the person who threw the thing near him which would be virtually impossible. Even if you could identify that exact specific person, his comments after the game show he really didn't fear bodily injury.
Now, I'll bold this too because its implied in the last portion of your question and a lot of people in the media ignore it, but I think it is important.
SEC PUNISHMENT.
The SEC is not a state actor, it is a private entity. So as a private association, it has to have a set of defined rules and can't act arbitrarily or capriciously in it's dealings with its private members. the SEC has a stated rule that talks about interference with the field of play, and it sets the monetary fine at $250k for 3rd and subsequent offenses. It also allows the commissioner to add additional penalties as they deem fit. If the SEC imposed a fine of, say, $500k, Tennessee would have sued and said the SEC was acting arbitrary and capriciously by imposing a fine above and beyond their outlined rules. A private actor can't just ignore their own rules and claim due process. As to the "other penalties" language that obviously is written for non-monetary penalties. Ergo, the book report we have to submit for "punishment" purposes.
