What is the ruling on blood that appeared after sexual intercourse but was not discovered until morning, and what is the ruling on delaying the ritual bath (ghusl) from janabah for eight hours?

There is no sin upon you for the intercourse that occurred, as long as you did not know about the menstruation until after it. And there is no sin upon you for delaying the ghusl for this period of time, unless you deliberately delayed it until the time for prayer had passed. In that case, you bear the sin of intentionally abandoning the prayer.