Complex sentence: Line 9 was originally proposed to be extended future north and west to Haidian Shanhou but has since been replaced with Line 16; currently planned to be extended to the north towards Collage Road (学院路), where it will interchange with Line 15.
Split into simpler sentences: Line 9 was originally proposed to be extended future north and west to Haidian Shanhou but has since been replaced with Line 16. It is currently planned to be extended to the north towards Collage Road (学院路) where it will interchange with Line 15.