I've only made one batch albeit a successful one But i'd say buy botteld water. Bottled water is probably much cheaper than messing with water ph. I use Baby water, its distilled and then has the minerals that should be there added back in.
Water pH really isn't very important. What is important is alkalinity. Either get the alkalinity number from your supplier or send a sample off to Ward Labs. Unless you are one of the fortunate few with very low alkalinity water the simplest approach is to dilute the water you have with low ion content (DI,RO) water until the alkalinity is low. Then follow the guidance in the Primer in the Stickies and step off from there as your experience increases.
Knowing the pH really does not give you the full story. What is the level of bicarbonates? Think of the pH as a balance beam with weights on each end. pH 9 means that the balance beam is tipping towards akalinity but your not know how big the weight is that is tipping the scale. To balance the seesaw you need to know how much weight to add to the other side. Make sense?
I'd suggest getting a water report and use one of the popular brewing spreadsheets to figure out how best to treat you water for each recipe.