There isn't a single "official" mod, but these are the most reputable options for 1.8.9:
Achieve a consistent 10–15 CPS without the physical strain. auto clicker mod minecraft 1.8.9
This makes your pvp easier by automatically clicking for you at a random CPS range, no need to spam manually anymore. First, use / CurseForge SaiCo Auto-Clicker - Minecraft Mods - CurseForge There isn't a single "official" mod, but these
When choosing a mod, look for these specific settings to avoid immediate bans: There isn't a single "official" mod