when the akatsuki had bee's substitution his tentacle had some power of the eight tails, and the jar obito went for at the coast war that had some of the nine tails power in it
It merely needed a sufficient portion of each Bijuu's chakra, and the Kin & Gin brothers portions was sufficient for the Kyuubi piece and the Hachibi's sacrificed tentacle provided for the other.
when the akatsuki had bee's substitution his tentacle had some power of the eight tails, and the jar obito went for at the coast war that had some of the nine tails power in it
Sasuke failed to capture the Eight Tails and instead had a clone that looked like Killer B but was actually a part of one of the Eight Tails. Thus containing some of the Eight Tails chakra.
The fight on the coast with the Gold and Sliver brothers who where eaten by the Nine Tails they ate the flesh inside the Nine Tails to survive they later emerged from the Nine Tails with partial power of the Nine Tails. Darui sealed them in the Hidden Cloud Villages sealing jar (I forget the name) then shortly after Tobi (Obito) stole the sealing jar due to the fact that some of the Nine Tails chakra was inside.