There is no Plumb Cut Option in the TrussMaker tool.
I have yet to see a truss with perpendicular ends and that is the ONLY option there is. I rarely use the TrussMaker tool for this reason as all the trusses are wrong in Section and 3D views.
It would be even better if all of the same options for the ends of the truss were available that are in the Roof Edge Angle options.