Too many variables. Veg a plant for 9 weeks. See how big it gets? Thats a pretty long veg time. Youre working backwards determining veg time first. I have 1 strain, Blaze, that seems to be a slow grower, though very bushy, that stretches very little in flower. 9 weeks wouldnt be to bad. Appalachin superskunk though, is a very vigorous grower and more than doubles in the first 3 weeks of flower. Get familiar with what youre working with.