Yes they are, the NBA has cameras mounted in the rafters for this specific purpose

source: https://www.washingtonpost.com/sports/wizards/nba-analytics-...

company behind the tech: http://www.stats.com/sportvu/sportvu-basketball-media/

Other leagues would likely do it manually with stats callers and spotters - literally one person calls out the stat as they see it, and the other enters it into the software.

NBA and technology have progressed to be able to justify doing it with cameras.

They have some great software/analysis whereby they can watch all players, note where they are and where they should be (based on opponent's shooting or penetrating ability) and then work out which players spend the most time where they should be.