I think last time someone asked this the consensus was they run a little big. The only reason I remember is because I had just ordered a pair and I remember wishing I had ordered a half size smaller. I usually wear an 8 and the Seychelles I have (the same ones from the time I'm talking about) are an 8 and they are a little too big. I would have returned them for a 7.5 but they were sold out of that size by the time I realized that I needed a smaller size.
I'd also say slightly big...actually I think they are cut wider than some sandals. My foot is slightly wide and I normally wear a 7.5 or 8 and the 7.5 in Seychelles was plenty roomy.
I normally wear an 8.5 so I ordered a pair of wedges in 8.5 and found that they were very roomy and I have wide feet also. They are not uncomfortablly roomy but every now and then I run into problems. If your feet are not wide or even just slightly wide I would go with the 9. I know a lot of people already answered but I just wanted to give you one more view. Thanks!