INCOME TAXES - Components of loss (income) before income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
U.S.	$ (121,245)	$ (338,565)
Non-U.S.	(2,997)	(13,884)
Loss before income taxes	$ (124,242)	$ (352,449)