I intentionally ignore this news and don't like the idea of sub-group, SNSD is 9 and SONE believe in 9. the first few pictures didn't help either, in fact, they were a insult to any groups that had debuted for years.
but since it is confirmed and Taengoo is my ultimate bias, I can only support her whatever she decided to do. at least I get to see her appear in more TV programs with more screen time.
fortunately, Taeyeon teaser looks absolutely great!