Here we have a clear example of Oliver Cowdery misreading satisfied as the visually similar sanctified. His correction was virtually immediate (there is no change in the level of ink flow for the supralinearly inserted satisfied ). As might be expected, elsewhere the text refers to satisfying the demands of justice, but never to sanctifying the demands of justice:
Summary: Maintain in Mosiah 15:9 the corrected reading in 𝓟: “and satisfied the demands of justice”.