Yeah, these are tough to size. I believe the D widths won't work for anyone with regular width feet. However, the EEE widths all have some serious heel slippage, though I think that's acceptable in a slipper. The 8.5EEE fit okay, but they're a tad tight, possibly from overly thick sheerling. The 9EEE is arguably a better fit for me, though this particular pair has more sheerling in the right vs. the left which makes the fit a bit off, and the stitching/finishing is a little sloppy. I'm trying to decide between the 8.5EEE and the 9EEE but I'm just not sure yet.
When you come to a final decision, I'd appreciate your thoughts on why you chose the size you did. If I feel one of the slippers you're sending back would work for me, I'd love to purchase them from you directly and send mine back to AE. My feet are a half size shorter than yours. I'm thinking the 9D or 9EEE would work best for me considering the 8.5D has my toes almost touching the front of the shoe.