Thanks, trying to take it slow since this is my first one, but would like to start wiring soon to train it in to my own style. Not sure how long it has been in this particular pot, though it seems to be fairly established. The guy at the nursery said that the wiring of the roots helped to keep it in it's small "bonsai" form, is this a myth?
False. the wiring of the roots doesn't keep it small. This Juniper is a small shrub, it is small by nature. The wiring of the roots is done to hold the tree in the pot. This wire can be removed if the tree is well anchored in the pot. The way a bonsai stay small is by you trimming, pinching, and pruning. It seems to me the tree needs a little more thinning on the right side, but it is hard to tell from the picture. I suggest you leave it alone, take care of it for a year or two, once you've kept it alive and healthy for a while it is time to style it.
My advice is, you can leave it as it is now, fertilize, water, take care of it, read about Junipers. Once the tree looks vigorous and healthy it will be ready for styling. The color of the foliage tells me the tree is fine, but not vigorous enough for styling. Pay attention to the lower branches on the right side, they might not get enough light/air. Wait until someone more experienced than me gives you an opinion on that though.
Also, don't worry about the visible roots.