I don't think you will really have room for two sofas. How many people do you need to seat on average?

If you use an ottoman as a coffee table, it will add seating when needed. And one side chair. Then hopefully you will have room for a floor lamp or a small table and lamp.

At least the front legs of seating is best on the rug.

Is that a slider at the top of your layout? I see the door but can't tell about windows.

Don't want arms of sofas to overlap. There should be at least 3' between the sofa and side chair. With a 9' room (108") and a small (75") sofa, you only have 15" each side to the wall. I'd center the sofa and put ottoman in front. Then a small side chair.

Or you could look at small scale sectionals. Then you'd basically have a room wall to wall with sofa.

Look at "apartment" size furniture, it will scale better in a very small room.

For a rug, consider going to a carpet store and seeing if they have any high end broadloom remnants that could be cut and bound to your measurements. That way you can get a perfect fit for your room. This can be an affordable way to get a great rug.

You have some fantastic advice already. My biggest tip for small spaces is do not overcrowd it with furniture. Smaller furniture will fit better.

Better already! Just get a longer rug so it will be under both sofa and chair legs, and at least 6" from the walls ( about 12" is perfect). Now you have room between the sofa and chair for a small table where you can set down a drink and a lamp. It's nice to have seating level lights in the room.

Is this a new or existing building?

Congratulations then, it looks fun to have three floors. For sure I'd make the small room at the top into my library!

If you post photos you will get lots of responses here.

Are you needing all new furnishings, or do you have things going with you?