On the day the National Football League season kicked off, four gambling companies either began offering more sports betting options in New Jersey or announced plans to do it soon. The Tropicana casino said Thursday that it had reached a deal with William Hill Race & Sports Book to offer sports betting in the near future. No timetable was given for the launch. Hours later, Caesars casino began online and mobile sports betting. The FanDuel sports betting app also went live Thursday, and William Hill’s was set to do so Friday. Both of those companies received approval last week to…