would I qualify for this GI Bill if I was in the National Guard?
If you entered full-time National Guard duty under title 32, USC, between July 1, 1985, and November 28, 1989, and chose MGIB between October 9, 1996, and July 9, 1997 you could get benefits, but you would also need other things to qualify
what if I was on active duty on September 30 , 1990?
It could help you qualify but you will need something else to be true also