My son played 3rd-6th and, in 7th grade, decided that he wanted to go back to playing soccer again. He also decided that he'd rather coach football than play, so he served as an assistant coach in the youth league this past season while also playing soccer. His younger brother, however, played football this past season and seems to have adopted it as his favorite sport.
As for robotics, my oldest was on the robotics team in high school. Started out with no real idea of robotics design, etc., so she started doing things like PR and fundraising. After her first year, she got involved in design and became a controller on the competition team ... the one that operates the "arms" or other toolsets during competition ... along with the driver and other controller. She's carried that on and competes with the robotics team in college too. BTW, if you haven't see these robotics competitions, they are a lot of fun ... especially after you get past the qualifying rounds and the gloves come off.