The thought just crossed my mind ^^
While training with Pa toad he was unable to fuse together because of the 9 tails meaning naruto had to use clones to gather natural energy from the earth.
Since then the 9 tails had been freed but then quickly resealed by the fourth meaning that Naruto has gained control over 9 tails and could be seen as taming the beast to a certain degree.
I think now the 9 tails is gathering the sage chakra inside of naruto and fusing it with its own chakra, this is represented by the eyes of Naruto in chapter 444 like how the 8 tails can take killer bee out from a genjutsu any ideas? agree?disagree? your views please^^