We are 8 pax group will travel to Chongqing on Dec. 27 and heading to Jiuzhaigou on December 28.

I heard at CQ Bus Station, only one schedule is arranged to Jiuzhaigou. The bus leaves at 08:00 every morning and shall take 11-12h to arrive. But I am not sure if it still exists. U may check it further. If not, you can take a high speed train to Chengdu first. Then go to Xinnanmen or Chadianzi Bus Station to catch the direct bus to Jiuzhaigou.