You have the latest firmware installed. I think i would go back one to the previous version. This is the previous version.
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/
iwlwifi-9000-pu-b0-jf-b0-43.ucode
You have iwlwifi-9000-pu-b0-jf-b0-46.ucode
Edit: Do you know how to do that?