6' x 9' rugs are just large enough to be considered area rugs. This is an ideal rug size for small spaces or for helping define a specific part of a larger room, especially with an open floor plan.
On Your Floor:
6' x 9' rugs can be used as the focal point for a seating arrangement.
This size works well to define the space at the foot of the bed.
Use in a small living room if you want the front legs of the sofa and armchairs to touch the rug.