I have a Brother MFC-9340CDW printer that's setup and running on the network. First I went through the Brother linux pre-install steps and installed whatever I needed for debian.
Next I installed the Brother printer software from here. I installed both the brscan 64bit and scan-key-tool 64bit.
Then I went to the printer and found its IP address, you could also nmap your local network for it. Next, configure your printer by using this command, just substitute the IP for yours:
brsaneconfig4 -a name=Office model=MFC-9340CDW ip=192.168.1.70
Then install and launch XSane:
sudo apt install xsane
Launch it by calling xsane