I think the point was that a state cannot discriminate unless it has a compelling reason. Since marriage is a basic right for humans there is no legitimate reason to deny a person that right based on race.
I looked at the Kennedy book and she did take a very broad approach to privacy. She did not use the right to privacy in the 9th amendment but privacy as it is protected by other rights--especially the 4th search and seizure and 1st right of association. The 1st, 3rd, 4th, and 5th were cited in Roe as support for the right to privacy in the 9th as illustration that the founders meant to protect our privacy.
True. But I believe you could not have the Right to Privacy without at least the idea expressed by the 9th. It didn’t have to be codified by the 9th, but since it is it’s that much stronger.