Same here. Updated from 8 to 9.0.1 on odroid c2 hardware and now most of
AAC stuff is broken. One movie with AAC 2.0 started working with stereo upmix switch, some other 2.0 did not. 5.1 is wonky too. Half speed audio or constant dropouts. This makes libreelec mostly unusable on this hardware as there were other problems with 8 version