Is there also a shuttlebus back from the Jiuzhaigou park to the airport?Or to Hualong and then airport?

Yes, the shuttle bus also go back to the airport from the valley and the shuttle bus needs to be booked one day in advance. You do not need to go to Huanglong and then the airport.

You are suggested to ask a contacting number from the bus driver to book the shuttle bus. On the departure date, you will be picked up at your hotel if you tell them your hotel's name when booking.

Thanks for the info. One more question: Can I go alone hiking or do you think it is too dangerous?

If u mean that you wanna hike alone at Jiuzhaigou or Huanglong, it is just fine, not that dangerous. Just take enough necessity in case!