make bomb or bomber a blueprint.
In that blueprint get actor own location and velocity, then find player actor, get its location and velocity.
Then google about newton mechanic, get formula for free fall. Add that relative speed of player and bomber. Formula should be about as hard as elementary school gets. Find when to release bomb. Add some margin for errors ie. do not release only whne formula is meet but at margin of +/- 2% or so.
That is most clean solution.