Testing the tank water can be useful when you are having a problem with the fish or plants, but at other times it is just a fun thing to do. Don't do anything to correct anything you see when you test at random like that. I am almost certain you have not calibrated your test kits, so you can't be at all sure the results you get are at all accurate.
You can lower the pH by adding CO2. You can raise the pH by raising the KH by slowly adding bicarbonate of soda. Neither does anything for the plants or fish that is useful. Instead of adjusting the pH, just acclimate the fish to the tank water before adding them to the tank. They will quickly adapt to almost all of our tap water parameters.
When fish are said to "require soft water", the person saying it is usually wrong. A very few fish do have to have softer than usual water, and a few do have to have harder than usual water. The hardness involved is KH, not GH. If you are convinced that your fish are genuinely in need of softer water, just mix distilled or RO/DI water with the tap water to reduce the KH. That will soon become a chore, and if you are like many of us, you will develop a desire for different fish.