Thank you all for all of your responses. I did just get a response from Celebrity stated that they have given permission from there onboard team and also sent an email stating so.
We will arrive in Athens on the February 11th but disembarking isn't until 12th. Does anyone know if there would be a problem leaving in the evening of the 11th to get a flight home early the following morning. Hope someone knows, I already have my flight booked.