I don't understand why no one out there (not even Huawei) in all these years has said loud and clear that the Mate 9 in the USA has not, and will likely never have, an official update to EMUi 9!
The phone has been updated everywhere else, so clearly it is a US-only issue, and definitely not a technical one. It is likely the result of either company retaliation to US prohibitions, or the provider's loss of interest, or the intervention of some US governmental agency. I too tried everything I could to get an OTA, without success but, even more worrisome, I have not seen a single post from anyone able to do that in the States! The only alternative we have is to root the phone and install something like Lineage OS. I loved this phone, but I am tired to wait for an update that will never happen. Sorry everyone!