Theoretically it's possible, if they just started scanning random bracelets - especially because Clover is handy with math, and could have done running calculations to get every number. If 9 didn't work, they probably would have. I mean what would there have been to lose?
I think that's just because she's insane, not because she couldn't get it. She might never have heard the thumping in the coffin (In the true ending, everyone who left before Junpei didn't hear it, presumably because Snake was unconscious) so se presumably left through one of the 9 doors. If she chose the one on the left she was screwed because she probably didn't have the keycard and I doubt she could solve the puzzle anyway. If she chose the one on the right She made it to the incinerator and found that 9 didn't work. At that point whether she survived or not depended on whether she could guess all the possible numbers in time, and if the possible numbers included 8.
She had 5, 4, 6, 7, and 3. 8 is possible, so I think she could get that in 9 minutes.
I guess it is improbable... she already has a 50% chance (right or left door) and that's worsened by the possibility of hearing thumping in the coffin, meeting another player, mental breakdown, and giving up at the q.
Haha well I'm the weird one. I just got to the end of the game and Clover killed everyone at about like 3 in the morning my time and I went HUH, acknowledged the music was really pretty creepy at times, then went to sleep.
I mean the music did creep me out and I was kinda silly in that I seemed to play it a lot after midnight, but yeah! I just sorta would roll over and go to sleep after shutting my DS ;;