Intended across
1A1ATrades alcohol onboard ship (5)[-----] Substitute alcohol for ale, and put it inside (onboard) ss, from ship.
5A5AIn favour of paid athlete (3)[---] Double-definition.
6A6ACurrent vehicle terrible (5)[-----] Substitute current for AC and vehicle for UTE.
8A8AObserve 500 leaving starting point (3)[---] Remove D (Roman Numeral 500) from seed (starting point).
9A9ADo date ventriloquist secretly (5)[-----] Event is a do, and hidden in the fodder.