It is possible to have one pullet that is much taller than her sisters.What about her being taller than her sisters?
But it is much more common to have a male be taller than his sisters, so yes that does suggest male (not a certainty, but definitely a detail to keep in mind.)
Assuming that one is also 9 months old, you definitely have some slow-maturing birds there. That does make it more likely that the bird in this thread could be male, if there is a brother who is also maturing very slowly.His/her brother lately started crow and never mated with hens.