Yes, 7:30 to 9:30. We found that most places had a similar schedule. Some even started at 8:00 at the earliest.
Breakfast included fresh bread, jams, espresso machine, cheeses, crackers, salami, cereals, fried eggs.... Considered a typical Icelandic breakfast. Other places also included fish.
Breakfast was delicious.
If I remember correctly it is something like 07.30 to 09.30 or somewhere in that ballpark, you get a good breakfast and it is included.
Get an answer from Volcano Hotel staff and past guests.