Board Thread:Questions and Answers/@comment-25086462-20151223220513/@comment-5398287-20151224022833

That used to be a possibility until Shunsui himself told Aizen that it had been about 2 years since his defeat - not 3, which is about how much time would have passed with the addition of another year-long timeskip, in addition to all the characters changing appearances again because that's what happens during timeskips. Kubo simply retconned it to 9 to fit the 9 theme of the arc.