The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.And the tenth:
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.The author of these constitutional sentiments, particularly in conjunction with the enumerated powers of Article I, Section 8, understood well enough issues of scope. Consistency in standards for weights and measures, uniform coinage, patent protection, national defense... these things may all plausibly contribute to contractibility. That is to say, common sets of standards liberate merchants and their customers from having to make nuisance corrections for state-to-state differences in tonnage measurements or specie error. Folks can plan more suitably when they know their goods won't be expropriated by bandits, domestic or foreign. Uniformity in standards extends the commercial foundation beyond simple, parochial, short-duration bargains.
You don't have to be F.A. Hayek to understand that not everything scales as well as uniformity in excise. If you're like me, you may wonder under what theory of wages should midtown Manhattan have the same minimum wage as Spearfish, South Dakota. You might also wonder what relevance political borders have to education, health, housing, occupational safety, or agriculture. The 9th and 10th amendments can be interpreted as a lens for government, allowing the central government to focus clearly on those tasks for which it is best suited.
When honored, the strong, focused central government amendments IX and X create is more meta-euvoluntary than a sprawling, porcine leviathan set to suckling ravenous cronies and hellbent on engineering ever more baroque sluice boxes to divert power and treasure into the grasp of beltway elites.