Cracks in a head are never good, but since it is not in the combustion chamber area, they may be a little hope. The exhaust valves are pretty deep, may not stand another valve job. I don't want to assume the head is aluminum, but your clean areas look shiny like aluminum, if it is, there may be further hope for repair. Cast iron cracks are tough to fix, but aluminum is possible. Your best bet, IMHO, is to get it to a reputable machine shop that can give the answers you need. Maybe there is a Volvo specialty shop that you can call? I say that because I use a machine shop in So Cal for all my vw air cooled engines(RIMCO). Maybe similar exists for Volvo?