Did he have any reaction when he had the egg? I know we get conflicting advice about when to introduce egg as around the world we get told different things! If he didn't have any reaction the first time, I'm sure he's not going to have a reaction again, but keep an close eye on him.
DD has had a scrambled egg almost every day since she was 7/8 mo. I use the whole egg and add milk before microwaving it. By microwaving it and adding plenty of milk you can make it really runny and soft, but you must make sure that the actual eggs are cooked, not still undercooked. I always buy lion marked eggs to be on the safe side!
They are such a nutirtious meal all in themselves!!!