1

Hello

next to Delphi is the coastal village of Galaxidi. There is a lovely place, which I recommend you for lunch and bed. You can easily find rent double rooms from 40 euros. When you leave Galaxidi to Kalambaka, you firstly pass drom Amfissa town. See the centre with the old market. Next towards Lamia you can visit the Vagonetto mining park (http://www.vagonetto.gr/en/). Next stop could be the Thermopylae Battle monument in Thermopyles.
20 kms before Kalambaka you will pass the town of Trikala. Visit the old quarter Varoshi and the castle. It s a nice live place to eat, meet people and overnight. Between Trikala and Kalambaka is the Theopetra cave. Finally 20 kms east of Trikala is Pyli village, with its famous stone bridge, Porta Panagia church and the old monastery of Saint Vissarion.

2

o_akakios, wouldn't that be too much for including in a two night trip?
I second the suggestion of Galaxidi but i i am puzzled with Trikala for an overnight stay (and i have visited the place).
If the OP has only 2 nights, i think the second night should be spent in Meteora, preferrably in Kastraki and not in Kalambaka. When there we have decided to stay a second night.

In Kastraki i can recommend Doupiani House

3

I think a lot depends on specifics. Those sites you have are very demanding, I don't know how fast-paced or slow-paced you are when visiting sites and museums, but an average visitor needs at least 2-3 hours for Delphi ruins plus 45-60 minutes for Delphi museum. On Meteora, it depends how many and which monasteries you want to visit, but I guess 45 minutes are about right to count or each one.
The above doesn't suit very much the 9AM Athens departure. You do not mention when you plan to visit, but currently (high season!) Delphi sites are open till 8PM but museum only till 4PM. If you plan to visit sometime later in the year, who knows...Plus assuming you cover the Athens-Delphi distance on 2 and a half to 3 hours, you'll arrive in Delphi at noon, the hottest and busiest part of the day. Assuming you visit museum first, you then have to climb up and down a hill side spread of ruins, and this is quite demanding even if you make a lunch break between museum and sites visit to recover from long drive. I think this is a long day, and although in terms of travel logistics some drive towards Meteora would make your life easier next day, I do not think there is any decent intermediate spot anyway, and you'll be quite tired by then. Galaxidi is about 30-40 minutes drive from Delphi, and you have to partly back-track towards Meteora next day, but it is true it is a charming town (assuming you visit some time soon. On winter is still charming, but somehow deserted). Arahova 10 minutes drive prior to Delphi coming from Athens, might be an other overnight option. It is a nice mountain village, busy at winter, quiet and on my opinion much nicer on summer. Delphi its self is not so bad either. In Delphi I can vote for Hotel Pan (ask for a room with a view) and you may want to check Syvilla,Pytho, Varonos and Leto that get good feedback too. Depending on dates, I am sure you may find lesser rates on those hotels than you budget. Locals seem to favor a very simple grill-tavern called Gargadouas in Delphi, for cooked food Vakhos and To Patriko Mas are semi-decent options. In Galaxidi, Tassos is famous for its fish food (but pricey too).
Delphi to Meteora drive is 5 hours non-stop, so I am not sure you'll find time for all those interesting things #1 mentions, at least not i you wish to visit some Meteora monasteries at the same day. (Amfissa is only 18 kms from Delphi, and you pass from its ring road to get towards Meteora so if someone wants to have a very quick look, I guess in theory you may drive through it, but I have to warn you that traffic inside this small city is really "heavy")
Timetable on Meteora monasteries is different of each one and varies on season, so you need to plan carefully according to what you want to see and do while there.A few hours spent there next morning beore departing to Athens might be necessary at the end. I think Meteora to Athens is around 4+ hours driving (?)
http://www.kalampaka.com/en/meteora/monasteries.asp

4

Thank you all for your excellent suggestions!