If I use Deathgrip to kill a unit at a battlefield and have Soraka at that same battlefield, does it recall to base exhausted if it had less might than Soraka?

Yes, if you use Deathgrip to kill a friendly unit at the same battlefield as Soraka, Wanderer, and that unit has less Might than Soraka, the unit will be recalled to your base in an exhausted state.

The Interaction

This occurs because Soraka's ability is a replacement effect (Rule 366). It intercedes during the resolution of Deathgrip's "Kill" instruction and replaces the "die" event with a different set of actions.

Sequence of Events

1. Play Deathgrip: You play Deathgrip targeting a friendly unit at the same battlefield as Soraka.
2. Resolution: As Deathgrip resolves, it attempts to execute the "Kill" instruction.
3. Replacement: Soraka's ability triggers because the unit would die and has less Might than her. Her ability replaces the "die" event with: "heal it, exhaust it, and recall it."
4. Outcome: The unit is healed, becomes exhausted, and is recalled to your base. Because the unit was saved and did not actually die, the "If you do" condition for the second part of Deathgrip (giving Might to another unit) is not met, so that part of the spell does not execute. You will still draw 1 card, as that part of the spell is not contingent on the kill.

This is consistent with RiftJudge FAQ #8731 and FAQ #9003, which confirm that Soraka's replacement effect successfully saves the unit and prevents the subsequent "If you do" effect of Deathgrip from occurring.