First of all, there is no such thing as a normal foot. Your foot looks normal because it's yours... Even at its most simplest, feet are narrow, medium, wide. And boots are narrow or medium, or wide and you match your foot shape to the best last shape.
Concerning sizing for boots, you have to ignore what you street shoe size you wear (9 1/2) and ignore what mondo point (27.5) size is printed on the box. The millimeter measurement of the sole (boot sole length) is the best way to start the sizing process.
For example, a 27.5 FT Booter has a BSL of 315mm and a 27.5 FT Dropkick has a BSL of 310mm. Both are "27.5" but their length is quite different and this will reflect in how they fit.
Long story short, if you don't know what your actual foot width is nor a rough idea of your BSL, then you need to sit down with a boot-fitter and figure it out. A competent boot-fitter will remove the liner from the shell and perform a shell fit to see if the shell has the right dimensions for your foot shape. Only then will you know if you have a boot that is the right size for you, not someone else or their opinion of what works for them. People's opinion on what works for them is irrelevant for you- you don't have their foot so it doesn't matter what works for them. Find out what works for you.
WE ARE SKIING.