Catalysis of the reaction: (6aR,11aR)-3,9-dihydroxypterocarpan + H+ + NADPH + O2 = (6aS,11aS)-3,6a,9-trihydroxypterocarpan + H2O + NADP+. (6aS,11aS)-3,6a,9-trihydroxypterocarpan is also known as (-)-glycinol.
3,9-dihydroxypterocarpan 6a-hydroxylase activity