I can just perfectly picture 9 with Amy and Rory. Can you imagine 9 and Amy getting in a snark-off? She wouldn’t let him call her an ape, that’s for sure. And Rory would just kind of hang on for the ride but 9 would be pretty impressed when he manages to diebutnotdie repeatedly and they’d eventually build a mutual respect bromance type thing.
‘Course, 9 and River is a whole other headcanon that would probably take a few tens of thousands of words of fic to get nailed down.