Would an E9 comply if ordered to attention by an O1?

In all technicalities yes he must comply. But the following shit storm will be funny to watch.

it is in the oath we take . I feel it would hold a little more credibility to the position of O-1 on up if the person coming into the officer ranks has at least an E5 befor they are commissioned. I feel there would be less of a breakdown of leadership. too many officers get a power trip because of a butter bar then end up getting people killed for stupid shit.

He would have to respond but I feel sorry for the LT

A outstanding Chief would comply for the sake of subordinates. However, I do believe that a private conversation will happen very soon afterwards.

I have seen both sides of this. Hash marks don' t always equate wisdom or competency. All junior officers are not idiots. You respect the rank and not the man or woman wearing it. There is a chain of command for a reason. I once saw a First Sargent attempt this with a Second Luitenant and was eaten alive by him. Second Louie was exactly right when he said you may not respect me but you will respect this pointing to his gold bar. There are plenty of examples on the other side. The best senior NCO's avoid this kind of dust up by establishing their worth not through bluster but rather competence.

He would sat that Lt straight

It's a lawful order and should be obeyed. You don't have to like it and can report if you feel it is retaliation for a disagreement.

As a professional NCO he should. He knows there will be another meeting in the Commanders office that will have corrective actions.

Yes. 2 Lt. Probably not going to like the ass ripping he's about to experience

Yes