1st i find it hard to believe your pH is low. You said run off was ,5.2, and miraculously had done a slurry test at 5.2
If so
Using 9.0 water will not bring the soul pH up, just not how the real world works. You need to amend the soil to do that
Id seriously just move forward
You flushed it
So move on now
Also there is no way, in just 3 weeks, the amendment in the soil, pH buffers, would be gone
How did u do the slurry test my friend