I am doing solo almost the same time Sept 21-29. I have taken trips to the beach solo. I have done Universal Studios and Sea World solo. My 1st solo Disney trip was last September. It's very easy to do WDW solo.
You plan out your ADRs and your fast passes so you have a general plan of where you are going when. However you still have the freedom as a solo traveler to do what you want so if you want to ride Everest single rider line 5 times in a row you can.
I would recommend bringing a battery charger for your phone. I use the
MDE app in the parks to keep track of FPs and ADRs. Plus I like the wait times. Waiting in line, you can talk to the people around you if feel like it. Most of the people in line probably have their faces in their phones.
Sept will be Food and Wine Time at Epcot, it's a great way to spend a day grazing around the world. Being at the French Quarter, you can take the boat to Disney Springs, there are several good restaurants there and lots of stores to browse.
I like to take photos of the stuff that I'm doing and send it to my friends back home. This trip I have to go to the Anna & Elsa meet n greet and get Elsa to make a shout to our my friend's 3 year old son who thinks she is super cool because she has powers. I met them last year, I felt super awkward because I was an adult with no kids. It's less awkward for character meetings when they aren't face characters so you don't have to have a conversation with them.