We are in FL and our AC is always set at 80. It's been a dramatic saver for us, and we raised the temp a degree every two or three days to help us adjust before going any higher. Over time, we became comfortable and the saving has been almost 20 percent.
That being said, it seems like that is a pretty dramatic temperature fluctuation for them to go through in a short period of time. You will be putting them in the crates then the temp will raise 6 degrees or so during the course of the day. They might really feel it. If it was going to be a stable, higher temp that they could adjust to I would think they would be fine, but being confined then having the temp raise that much might be hard on them. Maybe you could try it on a day when you could be home and observe how they do? Either that or raise it only a degree or two while you are gone.
For what it's worth, last year after major AC repair issues, the repairman told me to never expect my thermostat to rise quickly after it's been hotter than usual in the house because everything holds heat, and it puts a drain on the system.