12x9s aren't that pricey, but you could always go with an 8x10. Don't ever go smaller than an 8x10 though or it looks cheap. 8x10 is pretty standard sized and I have that size in nearly every room.

I think it depends on what you want to achieve. I think if you have a big space and you want to make it feel like a room (versus scattered unrelated furniture) then you want to put on the rug. If it's a small space, I believe you don't want legs on the furniture - you want more of the postage stamp look on the floor to make the room look bigger.

I researched this when I was buying a rug. Th concensus I found was that if you do the front or all legs, it's fine but be consistent. So if you have a chair and a couch, have them both the same amount on the rug. Partial is ok.

do all legs of the sofas have to be on the rug? hardwood underneath. if that's the case, we're looking at a 12*9, and those are insanely expensive.....
Can just the front legs be on the rug?