Answer: Cherries prefer full sun all day long, but if the full brunt of the sun reaches it all morning up through noon, then that is probably sufficient. Since it is on the west side of your house, and close to the building, this may not be the case.
Yellowing can be a sign of many things, but based on your description I would suspect overwatering is a possible problem. The planting hole with amended soil may be acting like a sump and holding excess water. Typically it is actually better to loosen soil over a wide area to facilitate root growth rather than amend it and create an artificial environment separate from the native soil.
Also, it is unfortunate that the root ball was so disturbed as this can have a strong negative effect on the root system and overall well being of the tree, especially if the roots were allowed to dry out as a result of being exposed to the air. Sitting above ground outside at home, away from the nursery environment where watering is carefully monitored, can also have a negative effect on a tree. So there may be a number of factors at work here to shock the tree.
Since it is a new tree (and a nice expensive one) I would strongly suggest you contact the nursery immediately for assistance, especially if there is any type of warranty on it. They should be able to help trouble-shoot the site, the planting technique, the watering situation, and so on.
In addition, your local county extension may have some insights based on a description and foliage sample, an on- site inspection, or familiarity with the soil, location and current weather conditions.
I'm sorry I can't be more specific. Good luck with your tree.
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