I have 2 children adopted from China. One has anxiety, is obsessive compulsive. She doesn't have specific things that set her off, but being tired definately make it worse. We will be using a stroller this fall. My daughter is 9, will be almost 10 when we go. She has no mobility problems whatsoever. With a stroller my child can pull the shade way down and decompress. If she's anxious she can be upset with people taking little notice.
People are just going to have to deal. Don't feel bad and just do it.
Also, you will be asked if you can leave the stroller behind. I always get asked that. The cm takes one look at my child and assumes. I used to feel "guilty" (sometimes start the vacation still feeling so) and leave it in stroller parking. Then my child has a major meltdown, and we both end up crying as I sit with my daughter and wish we could be the "normal" Disney family everyone assumes we are.
Just do what's best for you. It's been said here before... "will this help my child have a better experience?"
Be strong mama! Do what's best for your child!