Is possible to buy a online ticket from Jiuzhaigou to Chengdu?

Well, the online booking website doesn't have English version. So if you know some Chinese, you can book the tickets online by yourself. Or you can buy them when you arriving at the bus station. In usual time, there will have enough tickets for you to purchase. Don't worry. You can try to call 400-660-8787 and consult more information.