Ghosts (US) has been officially released on DVD, but not on Blu-ray (as of 2026). Most HD versions come from web-downloads (Amazon, Paramount+, Apple TV). Therefore, a "BD9" for this episode is likely:
If your request specifically mentioned a release (a DVD-9 format often used for high-quality standalone episode rips or budget releases): ghosts s01e13 bd9
If you saw this labeled on a torrent, usenet post, or Plex library entry, it means: Ghosts (US) has been officially released on DVD,