Board Thread:Wiki Discussions/@comment-25217769-20140723231559/@comment-17623-20140724121300

Who knows. Perhaps he used Nine-Tails because all present had to deal with the Nine-Tails? Perhaps because it's the most common tailed beast. Indra or Asura could very well be a junchuriki of all or one of the tailed beasts. It isn't clear.

But the Nine-Tails is part of the Ten-Tails, hence why it could be used.