Yes, if a Legion or Horde is destroyed by an effect outside of combat (such as a card or quest), the player who triggered the effect receives the VP and any bonuses listed on the bottom of the card.

This is supported by the following rule:

• On page 47, under Legions:
  "If a Legion is destroyed, resolve the effect at the bottom of the card and remove it from the game. If you generate an effect that destroys a Legion, generate the bottom effect yourself."

This means that whoever causes the destruction of the Legion (or Horde, by analogy) is the one who receives the VP and any other effects shown at the bottom of the card, regardless of whether the destruction happened in combat or by another effect.

Source: page 47.

Source: Core Rulebook (pp. 30, 36, 47, 52, 60)