My T has never directly given me transitional objects, but the first time he gave me a tissue, he actually gave me two, and since I didn't use one of them, I took it home and still have it. I also have a reminder for an appointment he once wrote, I keep all his texts, and I write down every single session we've had in as much detail as I can remember. I look at these things or hold them when I need a reminder of him or feel closer to him.
He knows about it, he's fine with it. He has never suggested to consciously create a transitional object, but I think it'd be something that he'd only talk about/do if I brought it up first. He seems like the type to give me something if I asked though.

If you feel it'd be helpful, maybe ask your T after he's back?