Hajime really is pretty obvious, smiling as soon as he sees Sainami.
And of course Sainami isnt just going to give the other ticket without a little teasing, but theres no doubt who is going along with them. Sainami is kind of just as obvious honestly. XD
(But I do kinda hope we get more of an eventual answer on how they really both see themselves like the teachers were talking about. Hajime seems happy whenever Sainami still treats him as a guy, so thats probably already the answer but Sainami, while clearly being the more feminine and fine being seen that way, is still a bit up in the air. Or maybe it really just doesn't matter.)