Debarkation in Buenos Aires...

we end our cruise in Buenos Aires with an overnight on the ship (celebrity). Trying to find out how early we can leave the ship on the 2nd day since the ship was cleared the day before. Can people go back and forth all night as usually happens in other overnight ports? Does the shuttle run 24 hours/day? We want to depart by 6am to make an early flight to iguazu falls. Any insight or experience would be appreciated. Thanks!

Did you find out the answers to these questions? What happened? Was this allowed from a Princess ship?