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

Hell No..if an E9 does that he/she needs to be demoted...

An O1 outranks an E9, simple as that. But as others have said, what are you trying to prove by just flexing your "authority/rank" just you because you can? 9/10 times, your senior NCOs are there to help you and mould you (as well as their subordinate NCOs) into the best leaders they can be so they can retire with the knowledge that (hopefully) the unit won't burn down the minute they hang up the uniform. You'd be foolish to break the wing they're trying to take you under instead of getting under it.

Ive seen it once. Imagine an old west movie, when the stranger walks through the door and you hear all the conversation stop, the piano player turns to look and you just know some shit is about to go down.

First NTC rotation I was helping my Lt with some map overlays at the Bat TOC, our Battalion SMG was addressing some of the troops and a butter bar decided to interrupt and verbally correct him in front of said enlisted. SGM appeared to momentarily suppress his feral instinct to gouge out the butter bars eyes, then politely invited said butter bar into the battalion TOC for happy hour with the Bat CO. I believe the butter bar had a "come to jesus" meeting and exited the TOC 20 minutes later having seen the error of his ways.

When I was at Ft. Lewis, we were out back of the CP cleaning weapons and a 2nd Lt was walking towards us form the Battalion area, our SGM was distracted and walking towards him and offended the Lt. He locked up the SGM had him at parade rest , was chewing him out, SGM never lost his composure , 'Yes , Sir' , ' No, Sir' , as soon as the Lt was done speaking the SGM saluted and immediately went to Battalion , literally 3 mins after he went in, the Battalion Commander came flying out, chased the LT down , I have never seen someone so scared , he was white as a ghost, I think he actually soiled himself by some of the comments the BC was making to him, until I PCS'ed every time that LT saw that SGM coming he would run away.

Respect the rank if not the Man behind it - or get an Article 15. Remember, he is there to learn and improve and, if he is smart, will listen to his senior NCO, if he is lucky enough to have good one. Ultimately he is responsible for everything whether he is or not and for what his crew does or fails to do. Keep in mind, he is injured by a mistake far more than any EM. Its a tremendous burden. Go along to get along.

Nat'l Guard Readiness NCO (SFC) who had previously been Bn Ops NCO (MSG), Brand new SFC (acting 1SG for the weekend) tells him to stop what he is doing to follow HIS orders, (oh, and former MSG has more years in service than new E-7 has alive), the shouting started and all of the rest of us left the room and closed the door behind us. Shouting went on for a while.

I guess the oath of enlistment stuff gets tossed at a certain pay grade. And if a CO is facilitating it, it's even worse. Whatever circumstances that would even create such a situation should have been avoided, but regardless of your crust level a zero is a zero and unless he or she is giving you an unlawful or downright death to everyone order just to save their cat...why wouldn't they. Even at year 20 when a butterbar showed up, I stood up, still sprinkled in a sir or ma'am and carried out the plan of the day even if they needed some advice to smooth out that plan. I did witness the Bn SgtMaj flick his cigar at a LT when he asked if he was going to salute him. The CO backed SgtMaj up and literally crushed him in front of a bunch of LCpls. He spent the next year just lurking in the shadows until he PCS'd. Stuff like that does have a negative affect. Suck it up or try your best to avoid it.

I honestly could never imagine seeing an E7 or above, especially an E9, ordered to attention by an O1.. I'd imagine that kind of stupid wouldn't last too long in the military. If that O1 doesn't believe in God, he might want to start, because you know pretty soon he will be praying everyone forgets about it. The CO and everyone up to the CO will put the fear of God in him.. All I know is, were such an O1 to make it out alive from his "mentorship" training with his Senior Officers, that E9 would probably receive the best service and utmost respect from the O1.

I once witness an O3 (Marine Captain) talking rudely to a Master Chief (E9) without disregards for who was present or not. The Master Chief listened and answered professionally while standing at attention. Sure enough, once the Master Chief boss came back to the office, the Captain was standing at attention in front of a CAPTAIN answering for his unbecoming an officer. I hated that environment and culture. Good thing I got out when I could, otherwise I would've punch the hell out of that officer that spoke to me like I'm some sort of idiot.

PO2. Yes, but in most cases the 2LT will get some attention afterwards. I had a couple of situations as
a 1stSgt with a 2LT and with a Capt. I did not back down but made a extra effort to remember I was dealing with officers. The Capt was the Sqd Maintenance officer and also the EOT officer. He was just one of those persons I could not get along with. I had the trouble in both with the Capt. As a MO and EOT officer. I did come out ahead.

Technically.............

leagally yes but after i wouldnt want to be the 01 standing in front of the co's office

Yep, and a LTC, MAJ and CPT would make that 2LT's life a living hell. Not to mention the "extreme details" his Company's NCOs would insist on following his future orders (provide they were safe).

If I were the E-9, yes, but I believe me and a certain young butter bar would be having a little discussion later in private.

Well,I can tell you on the army an E-9 would definitely put a boot in that O-1's fourth point of contact. But on paper yeah, they are supposed to.