I've noticed that Moto's run pretty small, normally I've got a 9 (loose) and for boots 9,5. First tried a 9, but it hurt like hell when I walked or snowboard for a couple of hours, with the 9,5 with molded insoles all troubles gone. Don't know if the ION's got the same profile then Moto's.
Nevertheless always beter to fit in a shop first , I bought the 9's in a local shop and the 9'5 online, because the 9's where pretty messed up during the break in period. Boots also didn't really packed out a lot after a few months...