I have parsed it down to two brief posts. This is the background and intent of the Ninth Amendment in that context. The plain language using seventeenth century definitions and word usage, gives the same intent.
Number One.
It is important to understand that the Ninth and Tenth Amendments were drafted at the insistence of the states to limit the federal government from a broad interpretation of Article I powers. This demand aligns with the legal English of the Constitution of
potestas stricte interpretatur government powers must be strictly interpreted, and
in dubiis, non praesumitur pro potentia or the presumption is not in favor of a power.
The states' proposals conveyed powers denied to the federal government, not the grant of rights not enumerated. Example the Virginia Ratifying convention’s seventeenth article:
That those clauses which declare that Congress shall not exercise certain powers, be not interpreted, in any manner whatsoever, to extend the powers of Congress; But that they be construed either as making exceptions to the specified powers where this shall be the case, or otherwise, as inserted merely for greater caution.
Madison’s proposed Eleventh Amendment on June 8, 1789, was based on the states’ insistence of a limitation on the federal government:
The exceptions here or elsewhere in the Constitution, made in favor of particular rights, shall not be so construed as to diminish the just importance of other rights retained by the people, or as to enlarge the powers delegated by the Constitution; but either as actual limitations of such powers, or as inserted merely for greater caution.
Congress pared it down, after several modifications, to the current language:
The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.
The new language did not change the meaning or intent of Madison’s original amendment. But the states did not accept the new language. Madison explained that the meaning did not change.
Edmond Randolph was the most vocal objector at the Virginia ratifying convention. Madison addressed Randolph’s persistence after Madison had explained that the meaning of the Eleventh Amendment did not change to the Virginia ratifying convention to Washington in a letter dated December 5, 1789, noting that there was no difference between the original and new amended language of the Eleventh Amendment and that they both prevented the interpretation of Article I powers to be broadly interpreted to expand the federal government’s powers:
The difficulty started agst. the amendments is really unlucky, and the more to be regretted as it springs from a friend to the Constitution. It is a still greater cause of regret, if the distinction be, as it appears to me, altogether fanciful. If a line can be drawn between the powers granted and the rights retained, it would seem to be the same thing, whether the latter be secured, by declaring that they shall not be abridged, or that the former shall not be extended. If no line can be drawn, a declaration in either form would amount to nothing. If the distinction were just it does not seem to be of sufficient importance to justify the risk of losing the amendts. of furnishing a handle to the disaffected, and of arming N. C. with a pretext, if she be disposed, to prolong her exile from the Union.