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

Of course, the E-9 would come to attention.

I've seen this happen personally...the CSM was absolutely professional and complied then later in the day the Battalion Commander fully informed the young Lieutenant on the true food chain of the Army.

I have to agree I would like to be a fly on the wall behind the closed door meeting.

Yes, the Senior NCO would comply, IAW rules & regulations, not to mention NCO professional decorum.
But, the young lieutenant's military career would hit a wall!!

Yes he would have to comply to the direct order from a superior officer.

Of course he would. But that butter bar needs to be looking over his shoulder. One of the worst chewings I ever had was by my company First Sergeant when I was the company XO. He did it without raising his voice and with total respect. If young officers don't appreciate the wisdom of senior NCOs, their careers will be woefully short.

technically yes for the E9 is outranked by the young lt - it sucks but that's our military. I disagree with the fact that a 50 year old E9 who has 25 years in the military has to salute and take orders from a 19 or 20 year old 2nd LT who has been in the army 1 year if that. That's our military though. They have no experience, yes one day they will and I feel that the young officers should respect the SR NCOs enough in such a way as to not put them in such a position - it's not right at all.

1 MEF Ball 07. I'm in the Band and we had just finished setting up, so I walked outside for a smoke before a 2 hour jazz combo set. Saw a SGTMAJ helping his wife out the car as a 1LT went by. SGTMAJ sees him and acknowledges him. Officer gets huffy and says " SGTMAJ I didn't catch that salute." The SGTMAJ stops, looks at him and says: "Climb up my chevrons and get it. " I laughed and got yelled at by both. Great night .

We had a weak platoon leader bring our Div CSM into our training area and I yelled out "At East!!" The CSM walked up to me, shook my hand and smiled. The 2LT said to me; "for your information SGT, a 2LT out ranks a CSM." I responded with; "well sir, once you are SF, Master Blaster, CIB and silver star owner, I will show you that same respect." He just looked at me with that "deer in the headlight" look and walked off.

Diamonds are trump 1SG, and there are only 2 soldiers in the Army that wear stars..Generals and Sergeant Majors.