We did essentially this trip (excluding Santorini) in 10 days a few years ago. The reason we did it in 10 days was because we gave ourselves two nights in Nafplio to get over jet lag. You do not appear to be taking into consideration the effects of a transatlantic flight and your ability to recover.
We arrived Athens drank a bunch of coffee, rented the car and headed off to Nafplio. Its a two hour drive. We had to stop twice to refuel on strong coffee. When we arrived Nafplio we were totally exhausted and just wandered around the old town on day two nothing strenuous.
Your plan is to do Epidavros then drive half way to Olympia.
I said all that so I could suggest that you can do your plan but you should reconsider your logistics. There are several flights a day from Athens to Santorini. As long as you have 2 hours for a connecting flight thats enough time. The 9:30 am arrival time suggests you are flying east coast to Athens direct. Thats a good thing. Even if flights get off late because its such a long flight they normally can make up for a late departure. We have departed an hour late and still arrived on time.
Lost baggage. If its lost the earliest its going to get there is the next day. No need to wait for hours to get your bag. They will hold it for you when you return tot he airport after Santorini.
Thee3rr is probably no better place than Santorini to get over jet lag. The views are so spectacular you can just sit on your balcony and take in the views for hours. Before you know it you are over jet lag.
Now fly to Athens and rent your car. Drive to Nafplio. You will enjoy it much more.
After Olympia take the northern Nartional road to Patras and cross the Gulf of Corinth and drive to Delphi not Meteora. arrive late afternoon and take in the museum and perhaps the lower site. Next morning get to the site early and you will have it to yourselves for about 2 hours. It will take the bus crowds an hour to catch up to you so that's the time to leave. Drive to Meteora arrive late afternoon or early evening. Visit the Monasteries then. It will be virtually deserted. Take your photos now because the next day there will be tourists and buses everywhere. Visit the Monasteries you want and either drive back to Athens that night or stay over a second night and drive back to Athens when you are fresh next morning.
Do your visit to Athens and away you go.
This plan allows you to do everything you wanted but allows you to do it with enough energy to actually enjoy it.
If it were me I would skip Olympia because of how long a drive it is. I would substitute Ancient Corinth and Ancient Nemia ( sister games to Olympia) and add that extra day to Nafplio but thats just me.
Olympia Delphi Meteora https://www.flickr.com/photos/stanbr54/sets/72157645469717811/
Nafplio and Peloponnese http://www.flickr.com/photos/stanbr54/sets/72157632094108982/
