Depending on the version of android shipped with your device.
If your device once shipped with Android 9 you better use Halium 9.
If your device is newer you'll have to try Halium 10 but it's not mature as far as I know.
For older devices unsupported when Android 9 was released you should use Halium 7.1 for Android 7.
If your device is even older than that I will not recommand to port...
After a few days I decided to try another vendor.img and out of nowhere reboots worked just fine. I still have no idea why the vendor messed up apparmor but anyway, if someone happens to have the same problem he could try using different vendor images.
@carlo afaik that command should work, granted my knowledge is mostly LOS 14.1 based porting on a Galaxy Note 4, if that command is not working, double check the documentation your following is for the correct version of your LOS source, as well as your source is complete and not lacking anything.
@nullterminator I have no porting skills at all for what you are doing except for you do need the device to be on android 9 after that nothing. You need someone who knows what is happening.