>>1645276Different gardening methods have different spacing. The 9 per square foot would be 4 inches between each plant in the grid. Square foot gardening also uses companion planting usually. So, there would be other types of plants around each square foot if you go that route.
This image shows the square inches for 9 plants in a square foot. Each color is one plant's room to grow. Row planting of bush beans is normally 3 inches apart, but the rows are 18-24 inches apart. Rows will have more work in the end because of the need to do weeding or lay down more mulch. The square foot gardening method helps suppress weeds with its tighter spacing.
>>1645331Yes, you can plant them now if the ground isn't frozen. Remember, a $10 tree needs to go into a $100 hole for best results. Don't skimp on the hole size and proper soil/compost you are putting into it for that tree species.
For cuttings, it is best to do it in very early spring or late winter right before the buds on the tree start to open up. Well, it does depends on the type of cutting, so read up...
https://homeguides.sfgate.com/time-year-fruit-tree-cuttings-61578.html 