Carl, the best thing to do is to go to a local golf shop and try them on.  The FJ line varies quite a bit from style to style.  In other words, if you are a 9 medium in an ICON, you might need a 9.5 narrow in the Sport line.  Best to try them on and see what is best.  Then you can be very confident making your purchase.

 

Todd, good idea but my shoe size is a 13A. I have never found that size in stock at any of the local golf stores to try on. I have always had to either have the store order them or go on line and order them my self. I have a pair of FJ Classics that are in the winter of their life. Bought them back in 1994. They are a perfect fit in 13A. I do have a pair of Icons in 13N that fit but I would love to try a pair of 13XN but the problem is that in my size are considered special order and if they do not fit you are stuck in most instances.

Go over to the FJ Forums and ask the guys.  They may be able to help with this question.