By Valerie Insinna and David Shepardson WASHINGTON (Reuters) – The cockpit voice recorder from the Boeing 737 MAX 9 jet that suffered a plug door blowout during an Alaska Airlines flight and carried out an emergency landing on Friday was overwritten by the time it was recovered, the National Transportation Safety Board chair said on Sunday. NTSB chair Jennifer Homendy said the flight data recorder and cockpit voice recorder were sent to NTSB labs on Sunday to be read, but no data was available on the cockpit voice recorder because it was not retrieved by the two-hour mark, when recording resta…