So yeah, breeders list 'flowering time' because germination and vegetative growth times are sort of moving targets depending on how you grow. For instance, you might go 12/12 from seed or you might scrog and keep the Veg to something like 4 weeks...or you might do a whole lot of topping and training and it could be 2 months of veg.
So it's easier for a breeder to give a 'flowering time' that's the weeks once you've flipped to 12/12 (or if you're outdoors, when the days get short enough).
...also, knowing that most people are looking for shorter flower cycles, many breeders miss-quote the time to finish so that growers think they'll get there earlier.
If you're just going to flower now, and it's 9-12weeks, you're looking at a harvest towards the end of October or November if your weather holds out that long.