I bought these in the winter for this coming spring for my 2 year old.  He was already wearing a 9W then, so I ordered the 9.5W.  Now, I don't know if he'll even grow into them by the end of summer.  Fingers Crossed!  I just thought the (8.5-9.0W) size would be too small since he had already outgrown 8.5s.  I would suggest ordering current size without worrying about future room, there will be plenty.