OK. Will download and try again.Are you sure you have unzipped the vendor image? Are you getting a message saying that the .zip file doesn't have the correct structure when you try to flash it in TWRP?
You need to click flash .img and flash the contents inside the zip for the vendor and boot images. The Rom zip has the correct folder structure to be installed from a .zip.
Also, use AROMA version of open GAPPS and ensure to click android 9.0 from the download link, then you can choose what to install. Note that you need to be careful with google phone app. If it isn't set as default an incoming call will crash your device.
Thanks for helping...
---------- Post added at 11:44 PM ---------- Previous post was at 11:43 PM ----------
Ah yes. I thought it is a model number. Anyway will try again.CSF9 is the build number. I assume you're using a Note 9 with model number N960F. Just make sure you've downloaded the correct zip and that it's not corrupted. Flash the vendor if you need to.
Sent from my Galaxy S9+ using XDA Labs
Thanks.