The point the other person was making was that the Constitution was ratified in 1788, but the Bill of Rights wasn't even a thing until 3 years later in 1791. The Supremacy Clause still holds sway, no matter of the existence of the Bill of Rights and subsequent amendments made.
The 9th Amendment simply states that the Constitution doesn't name every single right in the world, and that the people should not be limited to just those rights....as long as the rights not listed don't violate the supremacy of the Constitution over all other laws in the nation. So, while on one hand, the state and the people can claim a right, it isn't a right if it violates the Supremacy Clause.
Same for the 10th Amendment, but in the opposite direction where it limits government power to what is in the Constitution...as long as those limitations aren't done to limit the powers within the Constitution. So, if a state tries to pass a law that will limit legal authority of a power in the Constitution, that violates the Supremacy Clause.
The 9th and 10th Amendments do not just give carte blanche powers to the states or citizen that over-rule the Constitution. To do so, would nullify the whole point of the Constitution. They are not worded in that fashion. And the point and powers of the courts is to determine if said rights and limitations of powers as made by the states or the people is, in fact, in line with the Supremacy Clause...and NOT what the Declaration of Independence says about rights since THAT document has a different legal point and effect.