I doubt it will not crack again, you should start saving money for a new frame because it will crack again most likely, probably sooner than later. If your seat is raised so high that the seat post remaining in the seat tube is insufficient then your frame is too small or your seat post is not correct to your purpose (as in you need a longer one).
You cannot just lower your saddle, your saddle height is a function of your leg length, you cannot just suddenly grow shorter legs. If the saddle height was set correctly and there is not enough seat post in the frame, you got a problem.