10/4/18 Got a brand new Note 9 on 9/24/18. Battery Life was about 16 hours until I had an update on 9/27/18 . Now battery will not last more than 7 or 8 hours. I followed Samsung's 10 steps except a total factory reset. I got about 10 hours of light use. I checked each app battery use. Bixby Voice Wake up used 19% and is was not turned on. Settings used 19%. AT&T Find my Mobil used 19 % and Device maintenance used 19%. All my other apps used the remainder of the battery which was then at 11% . I can't delete these items. The phone store will give me a new phone but this appears to be a software problem from Samsung or AT&T.
Searching for answers.