9th Edition as well to a degree
You ignore characters with 9 or less wounds for purposes on whether another given character is the closest, you wouldn't ignore a 12-wound character for that half of the rule.
For the initial 3" "covering" on the other hand, the vehicle/monster keyword would be key. The character keyword is irrelevant for the first half of the rule.
The very rare 10+ characters (or any single-model unit) that are NOT vehicles/monsters (Triumph of
St. Katherine? Any others?) would thus not cover a nearby character with the 3" rule.
But for 8th, they obviously can. A sorcerer is protected by Magnus. A Tech Priest is protected by a character-Knight. A Broodlord is protected by Swarmlord. Etc..,etc.. (as long as the 10+ model is closer to the enemy).