More than 65,000 fans packed a stadium in Tampa to watch Tom Brady lead the Buccaneers to a win in the NFL’s season opener, just hours after President Joe Biden announced a sweeping new plan to slow the latest COVID-19 surge. Most people at the open-air stadium Thursday night didn’t wear masks. There was no vaccine requirement for fans, something Biden has urged sports and entertainment venues to impose. Many other football stadiums are taking a similarly lax approach to pandemic measures this fall, and that worries health experts. This fall’s crowded college and professional football stadiums could create ripe...