Does Arachnoid Horror enter ready if Wuju Master has level 11 and you deploy the Arachnoid Horror to a battlefield directly?

Yes, Arachnoid Horror will enter the battlefield ready if your Legend has already reached Level 11 and possesses the "Your units enter ready" ability.

Reasoning

• Active Passive Ability: The Level 11 ability, "Your units enter ready," is a passive effect. Since you have already reached Level 11, this effect is currently active and applies to all friendly units as they are played.
• Timing of Entry: Unlike a "When you play me" ability, which triggers after a unit enters the battlefield, a continuous passive effect that modifies how a unit enters play applies to the state of the unit as it finalizes and transitions onto the board.
• Application: The Arachnoid Horror gains the "enter ready" property from the active Level 11 effect at the moment it is played.

Sequence of Events

1. Preparation: You have 11+ XP, making the Level 11 ability ("Your units enter ready") active.
2. Playing the Card: You play Arachnoid Horror. Because it is a unit being played while the Level 11 passive is active, the modification to its entry state is applied.
3. Finalization: The Arachnoid Horror finalizes and enters the battlefield in a ready state.

Note: I could not fully verify this ruling against the retrieved rules.