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

YES.......like it or not. unless it's an unlawful order.

Um, funny story about that lol

Do it unless you want to retire early...

This reminds me of a story my old man (a retired E-9) once told me. My father prepared for the day with his 0-5 in the orderly room when a young 2LT walked in a fit yelling at all my dad's PSG's. My old man looked at the 2LT and asked "Sir, do you know what the maximum effective range of a 2LT is?" As the 2LT looked back at the CSM, my dad held up his two fingers as they touched. "This far" he said "now shut the hell up and let the colonel and I handle this"

Depends who has lost their military bearing.

Yes

you have to respect the rank not the person

I am here to read the story.

Yes. Staff sergeants and Lieutenants run the Army. Sergeants major work for senior officers and are traditionally viewed as their representative. Life would suck for a young LT who acted disrespectfully towards his commander, even through the commander's proxy. The NCO does have a duty to comply with the orders of a commissioned officer regardless of which end of the pay scale either falls.

The E-9 may comply because he/she is a seasoned professional, but the LT would likely be schooled up by his chain of command.