Sorry to hear of the demise of you camera.
If you get the Ikelite housing for the G9 with the optional short lens port, you can fit Inon or Epoque wide angle adapters. The short port does limit the maximum telephoto zoom you can use in the housing though, not that this should be a problem underwater where wide is more important.
Oly 560 ultra zoom sounds like it will probably also pose difficulties in getting wide angle adapters - in the main, ultra zooms are physically long lenses, needing long ports, which make using wide angle adapters difficult.
If wide angle is a goal, then perhaps you could start by looking at the Inon website (link) which lists all the cameras that they provide adpaters for. This can then form your shortlist.
I would suggest you look at the Canon Powershot A640, which was compared favourably to the G9’s predecessor, the G7, and retails at a much lower price, but there’s no Inon WA adapter for it… :-(
Good luck in your search.
Graham