As of writing this, Greninja nor any of the Kalos starters are in Sword/Shield. Therefore you cannot transfer a Battle Bond Greninja.
Battle Bond Greninja is, unfortunately, Shiny-locked in the one event it was distributed, back in SM/USUM's days. You can hack shiny Battle Bond Greninja, but you can't Soft Reset or Masuda Method.
Source: Experience and this.