The quake was felt across the central region, and people rushed out of buildings and homes, including hospitals, as aftershocks continued. Offices and schools were closed for a national holiday, which may lower casualties.
The temblor struck about 56 kilometers (35 miles) deep below Carmen town on Bohol Island and did not cause a tsunami in the seas around the archipelago.
At least four were killed on Bohol, said the island's Gov. Edgardo Chatto.
Four others died when part of a fish port collapsed in Cebu city, across the strait from Bohol, officials said. Two more people died and 19 were injured when the roof of a market in Mandaue in Cebu province collapsed.
Photos from Cebu broadcast on TV stations showed a fallen concrete 2-story building, and reports said an 8-month-old baby and a second person were pulled out alive.
Vilma Yorong, a Bohol provincial government employee, said she was in a village hall in Maribojoc town when "the lights suddenly went out and we felt the earthquake."
"We ran out of the building, and outside, we hugged trees because the tremors were so strong," she told The Associated Press by phone. "When the shaking stopped, I ran to the street and there I saw several injured people. Some were saying their church has collapsed."
She said that she and the others ran up a mountain fearing a tsunami would follow the quake. "Minutes after the earthquake, people were pushing each other to go up the hill," she said.
Chatto, the Bohol governor, said that a church was reported damaged in the provincial capital of Tagbilaran and a part of the city hall collapsed, injuring one person.
A 17th-century stone church in Loboc town, southwest of Carmen, crumbled to pieces, with nearly half of it reduced to rubble. Other old churches dating from the Spanish colonial period, which are common in the central region, also reported damage.
Tuesday is a national holiday for the Muslim festival of Eid al-Adha, and that may have reduced casualties because schools and offices are closed. The earthquake also was deep below the surface, unlike the 6.9-magnitude temblor last year in waters near Negros Island, also in the central Philippines, that killed nearly 100 people.
Regional military commander Lt. Gen. Roy Deveraturda said that he recalled soldiers from the holiday furlough to respond to the quake. He said it damaged the pier in Tagbilaran and caused some cracks at Cebu's international airport but that navy ships and air force planes could use alternative ports to help out.
Passenger flights were put on hold until officials check runways and buildings for damage.
Earthquakes are common in the Philippines, which lies along the Pacific "Ring of Fire."
Cebu province, about 570 kilometers (350 miles) south of Manila, has a population of more than 2.6 million people. Nearby Bohol has 1.2 million people and is popular among foreigners because of its beach and island resorts.