Stopover visit to Songpan Ancient Town from Jiuzhaigou

I have a flight departing from JZH airport at 1500 hrs. (1) Would there be enough time for me to catch an early bus from Jiuzhaigou, visit Songpan Ancient Town, before proceeding to the airport by 1300 hrs? (2) What time does the earliest bus leave from Juizhaigou and arrive at Songpan? (3) Is there any luggage locker at the Songpan bus terminal? (4) How frequent and how much time is the bus journey from Songpan to the airport?