Says buses start 10 minutes before end of game so will need to wait and see if that means main friendly or towards end of legends match. Be inclined to think they will run from end of friendly and continue on for a few hours
Main page
https://www.merseytravel.gov.uk/customer-information/everton-test-event/

Timetables https://merseytravel.adidocdn.dev/timetables/Bus/Everton-Stadium-PDF.pdf