I liked the idea behind the movie, but the movie itself wasn't very good. It was a bit like the movie Mickey 17, it didn't quite know what it wanted to be and tried to be a lot of things, but none of it really stuck and it ended up being a bit incoherent. The ending I thought was powerful though.
Why would you assume people that went on to have successful film careers failed high school science? Just because someone doesn't pursue science as a career doesn't mean they received bad grades in it, especially at a high school level.
Without regard to the broader point* in the particular case of Leo, I’d be surprised if he had great k-12 science education. He was a child star already at that point, right? Only so many hours in the day.
Of course, it isn’t a universal rule, see Dolph Lundgren, etc etc.
* I don’t care if the actor delivering an environmentalist message in a movie is actually good at science for the same reason I don’t care if Keanu Reaves knows king fu.