You cannot sit on the sill, but the couch is right next to the porthole. At least it was on our Cat 8 and i think the room configuration is the same in the 8's and 9's.
On our Panama Trip in May our Cat 9 had the bed 1st on your left as you entered the cabin then the sofa. THe Port Hole id great, you can't sit on it, but you have a shelf the whole length of the wall and can store lots of stuff on it.
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