I head canon that Nine cares a lot about his hair. Maybe not so much how it looks, but it itself means a lot to him. He believes that hair holds memories, so he swore to never cut it again after Sandor died. He’d never cut away those memories of him, or any of the memories that came after. The memories of his friends. He won’t even trim the ends, because if he trims it enough over time he’ll cut away all that he has of Sandor left.
With this importance established, I present the idea of Nine having others hair braided into his. Maybe it’s romantic, maybe it’s platonic (it’s romantic), but he definitely has a bit of John’s light hair braided into his. Adam’s too. it’s almost identical in color, but Adam’s has a different texture, more course and just a little bit darker. Both braids are on the underside of his hair, braided into the ends of the hair that grows from his neck, like rat tails. But he always pulls them forward to show them off. John’s is the left braid, and Adam’s is the right. He’s proud of it, he loves it. It means so much more to him than rings ever could
