Police said the ninth death occurred nearly a week after the facility overheated and eight other patients there died.
Police said the man is also accused of shooting at a home with black residents.
The protests have continued since a judge acquitted a former police officer in a fatal 2011 shooting.
The police chief said protesters assaulted police with bricks and bottles, and officers responded by using tear gas and firing pepper-spray balls. More than 20 people had been arrested, and 10 police officers had suffered injuries, including a broken jaw and a dislocated shoulder.
“Repeatedly, I was told that our case was being escalated to the highest level,” an executive said.
State investigators were probing the facility after authorities found residents there in stifling heat.
The storm's impact continued to reverberate through Florida, where millions still lack electricity.
Prisoner put to death Wednesday sang “The Greatest Thing” in his final minutes.
Hurricane Irma battered Florida, causing flooding and outages that spanned the state.
Florida officials said it could be days or weeks before power is restored. Flooding is expected to be a continuing problem in many areas.
