Well the 1:9 is the OPTIMAL twist for the 62gr M855 rounds. 1:12 may give some slight edge in accuracy, but I'm willing to bet you would have to placing near the top at your state matches to notice a difference.
It could just be your ammo. Try more brands till you find one that works well. Heck if my brother can get dime sized groups out of his 1:7 twist barrel with 55gr (at 100 yards) there is no reason why a 1:9 cant so sub moa groups.