Ruffles was like this when her thyriod started overdrive.

I put her in the spare bedroom with a huge dish of food. She has a soft place to sit in there and a few toys, and that worked.

I know, you said no extra bedroom. What about
- play time before you got to bed.
- you and Fenway in your room, kitty in the rest of the space with food and toys; you keep a squirt bottle to stop the meowing and scratching
- OR kitty in the bathroom with the food and door closed, night light on
- OR kitty in the bedroom and you on the sofa
-OR get a garage like someone else suggested.

Will be curious to hear if the vet had any suggestions.