If you’re doing a scrog, you want to fill 3/4 of the screen, then flip to flower and continue tucking the tops under the screen for 2-3 weeks. With 9 weeks of veg in 3 gallon pots, I’d also say to flip now. You shouldn’t have to worry about being rootbound in a fabric pot though as the roots are air pruned.
Ps...smoking on some Barney’s Wedding Cake now and it’s 🔥