I had my hardwood refinished then 2 weeks afterwards the hot water tank blew down in the basement below and the newly sanded floor buckled in a few areas directly above where the water had leaked in the basement. Is it possible for the moisture in the basement to have wrecked the wood floors above even though there's drywall on the ceiling in the basement as well?

It's not only possible it is very likely. Water, especially hot water swells wood.
Call your homeowners insurance agent right away. They can help!