9m2, for 9 months, two people, would have stayed too but something came up. We'd a bunk bed with no bottom bunk where I'd my keyboard set up for giving piano classes. We'd plastic plates and cups which we would hurl down into the sink from the top bunk when we were done. Absolutely loved that place, it was like Alice in Wonderland.

If you need to, sure. the structure makes sense for some cheap motel where rooms are probably not much more than 10sqm (and the bathroom is communal).

But I can't imagine comfortably raising a family in such a situation.