You play the revealed card as part of the resolution of Djinn of Wishes’s ability. Timing restrictions based on the card’s type (such as creature or sorcery) are ignored. Other play restrictions are not (such as “Cast [this card] only during combat").

If the revealed card is a spell, you may cast it only if you can choose legal targets for it. If you cast it, it’s put on the stack, then Djinn of Wishes’s ability finishes resolving. The spell will then resolve as normal, after players get a chance to cast spells and activate abilities.

If the revealed card is a land, you can play it only if it’s your turn and you haven’t yet played a land this turn.

If you play a card “without paying its mana cost,” you can’t pay any alternative costs. You can pay additional costs, such as conspire costs and kicker costs.