Six deaths in Florida have been blamed on Irma, along with three in Georgia and one in South Carolina. At least 35 people were killed in the Caribbean.
More than 180,000 people huddled in shelters in the Sunshine State and officials warned it could take weeks for electricity to be restored to everyone.
"How are we going to survive from here?" asked Gwen Bush, who waded through thigh-deep floodwaters outside her central Florida home to reach National Guard rescuers and get a ride to a shelter. "What's going to happen now? I just don't know."
During its march up Florida's west coast, Irma swamped homes, uprooted trees, flooded streets, snapped miles of power lines and toppled construction cranes.
Around the Tampa-St Petersburg area, where Irma rolled through on Tuesday, damage appeared modest. And the Governor said damage on the southwest coast, including in Naples and Fort Myers, was not as bad as feared. In the Keys, though, he said "there is devastation".
"It's horrible, what we saw," Scott said. "I know for our entire state, especially the Keys, it's going to be a long road."
- AP