If during a struggle defender crosses the line but raider does not then the raider is declared out or not?

No, raider will not be out and points will be given to raiding team in this case (when defenders enters the opponent team's court).

From General rules of play in Pro Kabaddi:

15. During the course of raid none of the defenders shall touch the raider’s court until completion of the raid. In case one or more defender touches the raiders’ court before completion of the raid they will be declared out and the opponent team will be given that many points.

The raider is safe if he manages to stay inside the opponents court while the defender touches the raider's court. but if the raider is thrown out of the playing area . each of the team gets the point

No, the raider will not be out. Only that defender will be out and the point will be given to the Raider side. See General rules on how to play Pro Kabaddi.