E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Nine Days Wonder (A).
Something that causes a great sensation for a few days, and then passes into the limbo of things forgotten. In Bohns Handbook of Proverbs we have A wonder lasts nine days, and then the puppys eyes are open, alluding to cats and dogs, which are born blind. As much as to say, the eyes of the public are blind in astonishment for nine days, but then their eyes are open, and they see too much to wonder any longer.
King: Youd think it strange if I should marry her.
Gloster: That would be ten days wonder, at the least.