Ill had the same Problem and ill found it, it is the google account, deactivate the automatic google sync service and you´re s9 + will run like new its an problem who is there since S6, an tip what sucks even more, an wake lock app who tracks the powerconsumption will NOT log this Event so you never find it when you didnt have root rights, or know where to look. (Took me 2 Years to identify this problem, however ill couldnt fix it! besides to deactivate the automatic google account sync.Its not an Third Party APP since the S6 it is the Google Account, even an Phone reset didnt helped for me.)
sry for my bad english.
