The 90 day period is just pulled out of thin air. Some of Bush’s nominations were left hanging much longer than that. In the early decades there were long intervals when Congress was not in session—Congressional terms began on March 4th but the session normally began in December, so in odd-numbered years you could go nine months without Congress being there to do anything about a nomination. It wasn’t until the 1930s that the date of when a session began was changed.
That is true
Original time of assembly of Congress stated in the Constitution:
http://www.archives.gov/exhibits/charters/constitution_transcript.html
“The Congress shall assemble at least once in every Year, and such Meeting shall be on the first Monday in December, unless they shall by Law appoint a different Day.”
As per- AMENDMENT XX
Passed by Congress March 2, 1932. Ratified January 23, 1933.
http://www.archives.gov/exhibits/charters/constitution_amendments_11-27.html#20
“The Congress shall assemble at least once in every year, and such meeting shall begin at noon on the 3d day of January, unless they shall by law appoint a different day.”