yes, although they tend to cause more trouble than they are worth. All depends which hermit and if you do a search in the forums there are plenty of topics on this.
I've had a aggressive experience with blue legged hermits...they are reef safe but will kill snails and other hermits for a shell...i had a huge scarlet..and it was killed by a smaller blue legged hermit and robbed of its shell and then the small hermit realized it was to big for him and switched back.... red scarlet tend to hide alot but never give problems...color is nice addition to tank too....