No. Grand juries are used when a prosecutor wants to bring a certain level of charges against someone. The prosecutor basically shows the evidence they have that would justify a case, and they sign off on the indictment (charges). While a trial is not a sure thing for either side, grand jury proceedings are basically a formality and it’s not uncommon for a prosecutor to go their entire career without failing to get a grand jury indictment.

If an officer-involved shooting is justified and there’s no reason to bring charges, there’s no reason to get a grand jury involved either.