Fruit
We tend to think of "fruit" in two ways in natural language. One is as food that grows on trees and vines, sweet and delicious, and able to be eaten without harming the plant in any way. Another is as the things we produce, what our work yields for the betterment of the world. These are obviously connected: we are like trees, producing things that "feed" the world in some way, just as the tree produces fruit that feeds us. It makes sense, then, that the idea of fruit in the Bible is bound closely to the idea of goodness. Fruits that are eaten represent the desire for good and the energy to do what is good; fruit that is produced is the actual good that we go into the world and do.
Day
Like other descriptions of time in the Word, "a day" or a number of "days" describe a spiritual state rather than our natural concept of time. A spiritual "day" describes a state of mind or a state in our relationship with the Lord rather than a 12-hour or 24-hour span of natural time. "Day" describes a state in which we are turned toward the Lord, and are receiving light (which is truth) and heat (which is a desire for good) from the Lord.