The problem with the ninth and tenth amendment is that the list of state's and individual rights that one can infer could be endless. Neither amendment can be satisfactorily reconciled with the Constitution's Elastic Clause.
Both amendments were included as a sop to those who who believed that any listing of rights would only constrain the federal government's limiting of those rights and to further elaborate on the principle of federalism.
Absolutely. But I don't think that requiring individuals to purchase something they don't want to purchase falls under Congress' power to tax or spend. It's not really even eminent domain. I can't off the top of my head recall a case in which one group of private individuals was required by law to purchase a product sold by another group of private individuals on an ongoing basis. This is unprecedented.
Why should the federal government be able to compel anyone to do this?
"When the snows fall and the white winds blow, the lone wolf dies but the pack survives." Winter is Coming Now this is the Law of the Jungle—as old and as true as the sky; And the wolf that shall keep it may prosper, but the wolf that shall break it must die. As the creeper that girdles the tree-trunk, the Law runneth forward and back; For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.
