Yah 9 inches is either a stunt, a runt or juvie size. Brick was 15 inches and nearly 4lbs. Raised in a 225 with tankmates. Waste output was a LOT even though he didn't eat nearly as much past a foot.
Glad you rescued those Os. who knows, maybe they'll tack on another inch or two in time. Stunted fish often look old (bent, lumpy, tatty fins) so it does add to the confusion of "ageing" them.