If I attack with a unit with Eye of the Herald and my opponent has Ahri legend, my recruit token gets -1?

To answer your question: Yes, the Recruit token will be affected by Ahri's -1 Might ability if it gains the attacker designation at the battlefield she controls.

Here is the breakdown of why this happens based on the rules and game mechanics:

Sequence of Events

1. Attack Declaration: You move your unit with Eye of the Herald to a battlefield, initiating an attack.
2. Triggers: Two abilities trigger simultaneously:
   • Eye of the Herald: "When I move, play a 1 [S] Recruit unit token here."
   • Ahri (Nine-Tailed Fox): "When a unit gains the attacker designation at a battlefield her owner controls for the first time each combat, give it -1 might this turn."
3. The Chain: Per FAQ #7341, simultaneously triggered abilities are added to the same chain. The order is determined by the players (non-turn player triggers resolve first).
4. Resolution:
   • Per FAQ #1966, Ahri’s ability triggers for each unit the first time it gains attacker status, regardless of whether it enters during the initial chain or later.
   • Because the Recruit token gains the attacker designation upon entering play, it meets the criteria for Ahri’s ability.

Key Rules and Clarifications

• Trigger Timing: According to Rule 383.2.c, triggered abilities evaluate their conditions after the inciting event.
• Ahri's Ability: As per FAQ #7243, Ahri triggers when a unit gains the attacker designation at a battlefield her owner controls for the first time each combat. Per FAQ #10125, this ability does not target.
• Ordering: FAQ #7341 states that all simultaneous triggers go on one chain and the order is determined by the players.

In summary, because the Recruit token gains the attacker designation, it is subject to Ahri's effect once the ability resolves, even if it entered play after the initial attack declaration.

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