Yea but he has always shared his chakara wit him even before naruto beated him so of course in the magna he joined em for a bit plus kurama hates madara lol
Well he managed that with Pein so I assume he'll manage the impossible with Kyuubi too. I mean Kyuubi is starting to warm up to him in the last couple of chapters, so that's a good sign
Kurama changed a little bit when started absorbing chakra from Naruto. But now i think they have a huge bond, not just with kurama , with the others too.
If we had a break in the war, I think Kurama will teach Naruto some powerful stuff.