Sidi advice

I'm 9 (43) normally, but 44 in Sidis. You might want to get a 45.

I have very narrow feet and there's room for a thick sock in winter. I add a 3mm volume insole thingy in the summer to take up the slack.

nimhbus you need to try on any shoe for a good fit, i'd say...go to a shop

My old size 44 road sidis were perfect. My new size 44 mtb sidis seem to come up a bit wider. That's the way it goes with high-quality 'handmade' stuff.