I don't know. Surely you can order from JBL. There's also eBay.
For the JBL 9.1, besides the missing 4 end caps, the USA doesn't get the USB cables/AC adapters for the rear speakers. I'm NEVER going to reattach my rear speakers to a sound bar every night just to re-charge them. I would leave them in the 5.1.
4 position. JBL promises 10 hours of charge, but users say it's really 4 - 6 hours. I don't want the speakers shutting down halfway through a movie, you know? Other regions get USB cables/AC adapters. Yeah, I probably have enough spare cables on hand, but it's the principle.