pH 9.6 isn't really that unreasonably high for tap water (it's raised to reduce leaching from copper piping as the tap water runs through), and regardless the mash will have enough buffering capacity to basically make the water pH unimportant.
That being said it does look like you have a sort of high Residual Alkalinity (I'm too lazy to do the math but with Ca2+ at 13ppm, Mg2+ at 19ppm, and Alkalinity as CaCO3 at 63 the mEq/L of Alkalinity will probably be outpacing the mEq/L of Hardness). Have you noticed this "harsh" flavor changing in intensity between pale beers and darker beers? If it's not as harsh in dark beers it could be that your mash is too alkaline and the orgo-acids from the roasted malts are lowering the pH in to range.
Also make sure that your either carbon-filtering your tap water or using Campden tablets. The water department uses chlorine (usually chloramine nowadays) to keep microfloral counts low and if you are not removing it then you could get a harsh, phenolic-like flavor out of the brew.
One other thing to do is to taste the first runnings pre-boil to see if you get the same harsh flavor out of that. If you're only trying the final beer you're unable to isolate the issue to the mash (i.e., it could be some sort of yeast off flavor).
