I use the water as it is; I have never added chemicals. I have been using this product for a long time. I am on an auto-ship subscription to help keep up with both routine maintenance & shortage when in high demand and unavailable seasonally.

typically I wait 24 hours before I add my betta to water.

You still have to cycle the tank in order to grow beneficial bacteria. Once u add fish their poop and food produces ammonia and u need the bacteria to combat that. Look up nitrogen cycle. 

Yes, you can use this for Betta. It's Chlorine, Chloramine, and heavy metals free. These are the primary chemicals you should be concerned about in your new water. Ammonia is a by-product of fish waste, so I should expect it to be free of ammonia. It states pH balanced, so I can only assume it's neutral 7.0. Shouldn't be a problem if you're changing less than 40-50% of the water at a time. If you're doing a 100% water change (like most people do with small Betta tanks), make sure you acclimate. However, this method isn't recommended.