Well, my guess is something is interfering with the test, so see if you can get someone with a well-calibrated pH electrode to test the water. If it is really that basic, it is possible the fish etc could adapt to it, but it is best to bring it down slowly. Dilute acid, either HCl or an organic acid like acetic acid (pure white vinager) would work, but the trick again is to do this VERY slowly over a period of days. Take a little tank water out and experiment with how much you would have to add to a gallon to lower it say from 9.0 to 8.8.
An even safer way is to do daily large (say 25% to 30%) water changes until things stabilize. That is what I would do.
Also, check your test kits against salt water that you make up. Wait 24 hours until things equilibrate properly.