SALOMONWomen's X Ultra Pioneer Climasalomon Waterproof Hiking Shoes for Men Trail Running

Q: should I choose a 1/2 size bigger when selecting size.So if ki wear a 9 I should order a 9.5?

I think you should. I normally wear a size 12, but it was a bit too short. Also, I have narrow feet and the normal size was too tight and they did not have it in wide.

Q: How much does this shoe weigh?

A simple Google search says 409 grams. This is from Soloman's site directly and is listed in the data sheet here on amazon.

Q: How to buy the European size 45? Size 11- 44, size 11.5 - 46. I bought both. These don't fit.

I typically wear a size 8. I bought a size 8.5 and it perfectly. Snug but comfortable.

Q: I usually wear size 9US, what size should i order?

I usually wear a 11 or 11 1/2 and found the 11 a little tight so returned it for the extra half size bigger and fit great. I would stick with your normal size unless you teeter between two sizes like i do, and if so go with the larger size.