At .96 it is already dry. Chances of re-fermenting are slim, unless as you say, you are going to sweeten a part of it. Then by all means us Potassium Sorbate or you will encounter problems. Also, your initial S.G. indicates a high ABV level for a blueberry. Have you sampled it and does it taste similar to jet fuel? I would think with those numbers it would have an extreme kick to it for a wine.
Just my $0.02.
Good Luck and enjoy.