You may also need to …
scene_page = Sketchup.active_model.selected_page
scene_page.use_rendering_options= true
scene_page.use_section_planes= true
scene_page.use_style= true
scene_page.update( PAGE_USE_RENDERING_OPTIONS | PAGE_USE_SECTION_PLANES )
Be aware that if you wish different scenes to have different styles, then the scene will need their own style. (It makes makes it easier if the scene page name and their style name is the same.)
REF: