If I have a Emperors Divide that was hidden at my bf with my Jhin and he survived turn, next turn I go and attack the other bf with Akali. Can I play my hidden Divide to get the Akali back to base since it's my turn?

No. Your hidden Emperor's Divide can only move units at the battlefield where it was hidden — the one with Jhin — not Akali at a different battlefield.

Per Rule 811.1.d.2, when you play a spell from Hidden, its targets must be chosen from among units at that same battlefield (where the card is facedown). Since Emperor's Divide targets "friendly units at a battlefield" and is played from Hidden at Jhin's battlefield, it cannot reach Akali across at another location.