Towards the end of Naruto Shippuden season 4, the 9 tail's chakra left Sora's body and then Yamato said that it will try to seek a new host now. Who was that new host? Did the chakra in Sora come back to Naruto, the real host of the 9 tails?
Short version: He was just a filler character...
Sora appears only in the Twelve Guardian Ninja arc of the anime. In the other arcs of the anime and in the manga he is not mentioned anywhere.
In other words, as readers and viewers of Naruto, we don't know if Nine-Tail's chakra, that left Sora's body, found a new host or did come back to Naruto, the real host of the Nine-Tails.