I completed the JMT last summer. I was hiking with 3 ground dwellers and was told beforehand that camp would NOT be made based on trees so that I could hang but strategically on mileage and what was in store for the next day. *Often we hiked halfway up a pass and camped above 10,000 ft to reduce a big pass climb the next day. I was able to hang every single night (16) except for one, of course Guitar Lake at 11,500 which I knew. 2 nights I had to get a bit creative, including my best hang job at Sapphire Lake. Those of you that have hiked here are probably thinking "no way" but on the southwest side of the lake about 300 feet up from the lakeshore there were a couple trees that I was able to make work, not the most ideal and I was off the side of a cliff, but made securities that if the tree snapped I wouldn't go tumbling down the side of the mountain. *It did provide me with an unbelievable view to fall asleep to and if I were to go back, I wouldn't change a thing.
Here's a video of that hang
I used a 2/3rd UQ to keep weight low combined with a 3/8" CC foam pad for extra insulation and the nights I would have to ground it (honestly thought it would be more like 4-5 nights)
So to answer your question, absolutely you can hang and I highly recommend it. *With a bit of creativity you can hang at 10,500+ so you won't always have to adjust your mileage based on hanging options. I was the only one on the trail hanging that I saw and several others that we camped a night test it out for a after hike nap and said they wish they had a hammock instead of ground dwelling.
Good luck and have a blast!