There have been many people asking in many different threads about the Jiuzhaigou - Chengdu road. Until now It has always been open to the PUBLIC bus that runs from Chengdu to Jiuzhaigou. The buses may have stopped for one or two days during August but that's all.
Travel agent's buses are not allowed on the road at the moment. This is why travel agents will tell you that the road is closed. They do not want to sell you a public bus ticket because they won't be able to earn commission out of you that way. When Chinese travel agents (like some in this forum) tell you something is not possible it is sometimes worth checking again (of course there are honest ones also). Some Chinese tour groups have been travelling on both roads but technically they are not permitted to.
Flights to or from Jiuzhaigou and Huanglong have not been affected.