I wear a 9M & bought a 9M with still plenty of room for thick socks for me. I believe they're true to fit & very comfortable walking boots =).
As far as the leather melting, I've never had any issues with that ever while riding my bike with any of the boots I own when my bike gets hot. Perhaps a passenger rider could answer that question.
I Ride: 2013 Softail Slim
10 months ago