Soulblade Djinn’s ability goes on the stack on top of the spell that caused it to trigger. It will resolve before that spell.

Any spell you cast that doesn’t have the type creature will cause Soulblade Djinn’s ability to trigger. If a spell has multiple types, and one of those types is creature (such as an artifact creature), casting it won’t cause the ability to trigger. Playing a land also won’t cause it to trigger.