None of the work done previously by Peach or by me helps in finding where Konno Hachimangu really is. Here is a writeup on it:
Konno Hachimangu
(3-5-12 Shibuya), a historical shrine said
to have been built in 1092. The Konnozakura
cherry tree to the side of the main
shrine has been designated a municipal
natural monument and is well known as
providing an unusual variety of cherry
whose branches bloom in both single and doublepetaled
flowers.
I can't copy this map, but it shows that this shrine is located very close to Shibuya station. This dovetails with the description boingo has provided to pass Three Minutes Happiness store on the way to Shibuya station. You can see the location of this shrine in the map at the top right of this link:
Konno Hachimangu Shrine