so tell us, how do the berries taste?
Pernettya is a genus related to blueberries & huckleberries (Vaccinium) and wintergreen (Gautheria), I would treat them similar. There are some nice examples of blueberry as bonsai. They have some issues, such as the tendancy to withdraw support from older branches in favor of new suckers from the roots. They all seem to demand fairly acidic substrate, and don't like fertilizers, water or media high in Calcium.
I have a Pernettya species myself. I forget which one, have only had it about 10 months, Mine looks similar to yours but younger, smaller, hence no berries yet. I have not been able to detrmine if the berries relly are intoxicating ir not. It is alleged that eating too many can cause delerium, but I have yet to get a single berry. There are numerous species of tropical and sub-tropical members of the blueberry family. There are some choice gems out there. Pernettya is one genus with a dozen or more species. I think they have good bonsai potential. I doubt anyone has tried yet other than you and me, they are rare in cultivation.