Olympus 9-18mm OR Oly/Panny 7-14mm For Video?

Hey Guys!

I'm into underwater video (currently own a panasonic GX7), and im looking to buy a new lens but not quite sure what to get.

Everyone seems to recommend either the olympus/panasonic 7-14mm lenses, or the olympus 9-18mm lens.

Could anyone share some advice as to the difference in underwater videos (even stills) between the 7-14mm and 9-18mm lenses?

Thanks in advance!

None of those lenses are stabilised with the GX7 in video. I get better results with the kit lens and a wet lens