hanging clothes take up 2 feet. so if you have hanging clothes on both sides of the 8 1/2' width, that only leaves you with 4 1/2' of walking space -- which is generous, but not enough to add another piece of furniture.

A peninsula may work but an island would make a tight space even if shelves on one wall and hanging on the other.

Hrhpri--I agree with Brenda and Amy. With a closet of this dimension, I would consider placing a 3' bench on opposite sides of the long walls, or at least on one side of the room opposite the door, as a full length mirror could be placed on the closet side of the door. Happy Houzzing.