9 siblings are left with joint ownership of the family home that most like is not sellable. What options do they have?

In terms of what? Is there an outstanding mortgage on the property? Even if the house has no value, the land does.

"Not sellable"? Why? No equity?

In that case, there are no available options other than do nothing and eventually let it go for taxes, or be foreclosed upon, whichever happens first.

Yes it can be sold - for just the back taxes, revenue stamps, and legal fees. Somebody wants it if the price is right. Put an ad in the local paper. First tell all the neighbors.