Ali,
Formative pruning is a term that is meant to describe pruning done on a plant in a juvenile state, so as to shape the plant. "Formative", because it provides you the opportunity to form the plant to a general shape you wish to achieve. Most folks grow these for the new foliage, so that's why I included coppicing as a method of pruning. However, mild pruning (heading each branch back to an outfacing "node" - away from the center of the plant), will cause it to sprout new growth in that direction. Conversely, you could just tip prune all of the branches by a few inches & observe its habit. If you want a full look, prune harder, but I'd wait until next spring. If you don't prune it, it will be more lax & lanky in habit.
Containerizing is a great idea, but perhaps only for the first 2-3 years. Understand that if it's outdoors in a container during winter, you will need to provide extra insulation as it will be above ground. Bringing the container into the house or garage, works well, though. It will eventually outgrow its container, so if you can figure out a great spot, plant it outside. It's a young one right now, so I would wait on planting outside.
