Just watched it again, missed a "pole". At what timecode is it seen? If it was mounted on the end of a pole, I'd say look up GoPro Hero rigs. Poles are popular with those. Probably one of those, with the iPhone attached.
It looks like a pole that is collapsed to the size of your fist. When you click on that link, X the movie closed and scroll down to the shot showing someone filming a girl looking at her iPhone. There is another gentleman holding a second iPhone up to communicate with FaceTime. The mount looks like it could be used with any iPhone in a case. So many of the mounts seem to need a proprietary case.
Do a Google image search for iphone tripod holder or iphoe tripod mount for more choices. Attach to the pole/handle/whatever of your choice. I like the looks of the Joby GripTight but haven't held it in my hand to know for sure.