I was told 9us in Dayton's sizing for 9uk in church's and 11.5 Adidas. will be measuring and sending them the measurements as they have shown using their measurement guide. i am still waiting for post of those who had their sizing done in Dayton's shop itself.
I thought that correlated to 8 on Brannock Device but based on what someone else said where they said they are 9->42 EU this does not compute.
What colour would be the most versatile?
UK sizes are usually considered ~ one size larger than US sizes, so 8 UK = 42 EU = 9 US. As others have indicated, you'd probably want to go down one to 1.5 US sizes to an 8 US or a 7.5 US. Since you're an E width (which is considered wide in US sizes), that may mean you'll only want to go down one to an 8 US.
As for colors, that's entirely your call, boss. You're looking at black, brown, or charcoal. All of them are fairly versatile. If you already have boots that you like and wear in one of those colors, maybe consider a different color?
I went with charcoal (which is nubuck instead of oiled leather), mostly because I already have some brown boots that I wear and I think the charcoal nubuck is a little more interesting and unique.