6s+ on 9.1 T-Mobile Phone
6s+ on 9.1 AT&T Phone
I just bought the T-Mo phone 2 weeks ago at Apple and even as of 2 weeks ago it came with 9.1 out of the box. Nobody is buying phones right now so they're sitting on months-old inventory.
Good for jailbreaking. Remember Apple has a 14 day return\exchange on iPhones, so if you go get one and it's not 9.1 or earlier, just return it, go to a different store, and re-buy until you get one with 9.1 .. totally worth it. I can't not have my jailbreak, using an un-jailbroken phone feels so slow and old.