Male olives tend to get bigger than females, all the big olives(12ft+) i've seen have been male. From what i've seen and been told females seem to top out at around 10-11ft.
Maybe Paul can shed some light on this, my olives aren't adults yet so i can't really be 100%.
It takes a few years for them to get that big. Belinda your intergrade will take even longer to reach 9ft.