mate, i think you're an L size, I am 12 so I am def. XL,
yup all of those rentals are horrible, couple weeks ago boot I rented gave me a big O shape blister, and I still see it, like many said here, boots are so important and now I know why.
I can't answer your question about the boots, but I want to know the answer too from a more experienced rider
2014 Never Summer Proto HDX 158cm
2012 Flow Trilogy Bindings XL