I've got a Shimano FH-M570, 7 speed hub for sale and i've been asked if an 8 speed cassette will fit onto it? I don't know so have looked online to see, but can't find a definitive answer :roll:
It looks to me as though your hub's been modified, with a 7-speed body in place of the original 9-speed one.
The locknut on the drive side is much further from the end of the freehub body than you would normally expect. The rubber seal on the other end is also wrong - perhaps taken from a front hub.