It's good that you unburied the graft, the tree looks well sited and planted well! 

In regards to pruning, you should wait to prune until the tree is dormant during late winter or in early spring (Jan-Mar). The risk of your tree contracting a serious disease is just too high to do any unnecessary pruning.

Since you are keeping this tree as part of a home landscape, you can allow it to grow with it's central leader. It should produce plenty of accessible fruit this way while also serving as a beautiful landscape tree. Most cherry trees are pruned to have an open crown, though, so if you are really trying to maximize production and make spraying easier, this is what you would do. It's really up to you how you want to manage the tree, though. Neither way would be wrong or harmful to the tree's overall health.

Here are some resources for cherry tree pruning:

https://www.canr.msu.edu/news/late-winter-pruning-of-fruit

https://www.canr.msu.edu/uploads/files/Research_Center/NW_Mich_Hort/Training_Pruning_Varities/TrainingTartCherryTrees.pdf

https://www.canr.msu.edu/uploads/files/Research_Center/NW_Mich_Hort/Training_Pruning_Varities/TrainingPruningYoungCherryTreesE1744.pdf

Again, wait to prune until January-March!