Dr. Greenthumb seeds and some of the breeders / pollen chuckers at Hemp Depot seeds have possibilities for September or early October finishes in northern latitudes. Both Greenthumb and many of the seed suppliers at Hemp Depot have been around a long time.
Some people have issues with Greenthumb's customer service and yield claims, but his stock has been used by Oregon Green to make a couple of her selections. If you take the time to mix Greenthumbs Iranian Auto into crosses, you can make your own quicker finishing stuff.
Delicious seeds has some fast versions of many of their outdoor selections. (never grew any of them). I can vouch for the "non fast" Eleven Roses outdoors, although last year mine finished in October rather than September in Maine. Decent structure and the smoke was good. Golosa wasn't something I'd grow again. Critical Star was okay. maybe even good.
Shout out to Getaway Mountain seeds too. He's got some that finish quick.
Bottom line as some have mentioned, it pays to chuck some pollen. A greenhouse, even a tiny one, can be helpful. Stick a few clones in smallish containers and use those naughty girls as your pollen dumpsters. Easy to move if they take awhile to finish and you can even hit some girls with multiple pollen loads from several daddies for some contrast to select through. If you really want to get freaky, reverse some girls and make some fem seeds. Again, one female can receive pollen from several donors, whether male or reversed female pollen or even both. Just make sure to mark down who did who and make sure to clean up when you're done.