Yes, it comes with a mount which is a plastic pipe with a pivot at the base. I'm sure you could mount the station itself on the same size pipe. The hardest thing would be getting it level. I'm not sure what diameter the pipe is but I would guess the outside diameter is around 1 in. The pipe in the picture is part of the base, and the unit sits over the end of the pipe. Hope this answers your question. 

I don't know the GoPro 9 but I think it's possible. Kind regards. 

I do not know GoPro 9, but every trumpet he is uncomfortable. Friendly help. 

Yes with the proper attachment on the gopro (threaded piece). 

Yes you can