If I bellows repeated choosing one unit in each battlefield can my opponent repulse to counter one of the triggers or both?

No, your opponent cannot use Repulse to counter either instance of your repeated Bellows Breath.

Reasoning

1. Repulse's Targeting Requirement: According to the text of Repulse, you must choose a friendly unit at a battlefield. It then counters an enemy spell or ability "that chooses it and no other friendly unit."
2. Bellows Breath's Targeting: When you play Bellows Breath with the [Repeat] cost, you are playing one card that will execute its effect twice upon resolution.
3. Total Scope: As established in RiftJudge FAQ #9655 (which specifically addresses this interaction), when you choose to target units at two different locations, the spell's targeting scope includes all units chosen across both instances of the effect. Because your repeated Bellows Breath is choosing more than one unit in total (one at each battlefield), it fails to satisfy the requirement of Repulse, which demands the spell/ability target exactly one friendly unit and "no other friendly units."

Summary

Because your repeated Bellows Breath chooses two units total, it is not a legal target for Repulse. The spell will resolve normally, dealing 1 damage to each unit at their respective battlefields.