LONDON—An Atlantic storm battered northwestern European on Friday with record winds of up to 122 miles per hour, killing at least nine people, knocking out power for tens of thousands, and shredding the roof of London’s O2 arena. Storm Eunice, which brewed in the central Atlantic and was spun up from the Azores towards Europe by the jet stream, posed a danger to life, Britain’s Meteorological Office said. The storm hit western England, making landfall in Cornwall, where waves lashed the coast, sending plumes of spray over the roofs of cottages, Reuters pictures showed. A woman was killed in London when a car in which she was traveling was crushed by a tree and a man in a vehicle in Liverpool died due to flying debris. Another man died after a vehicle collided with a fallen tree in the southern English county of Hampshire. In the Netherlands, four people were …