Isaiah 9

1 The Gentile Assyrians would overrun the northern parts of Israel. Later, however, the Messiah, Jesus, would use this region as His headquarters (Mat 4:13-16).
3 The "Jewish" nation would increase as Gentile believers were converted by faith in the Jewish Messiah, Jesus. The Jews that have faith in Jesus were (and are) glad to see this (obviously, those Jews that don't believe in Jesus see this all as blasphemy).
4 When Jesus came to earth, the Jews were expecting the Messiah to be a great military king that would free them from the authority of the Romans. However, at that time, Jesus came to free them (and us) from a far more oppressive enemy -- sin. At Jesus' Second Coming He will return as a great warrior and destroy all that have not believed in Him.
6 It is foretold that the Messiah would be born as a baby boy. This implies that He would go through the "natural" progression of baby, toddler, child, teenager, and adult. He would be human. Jesus often found that people had difficulty with His ministry simply because people He grew up around saw Him as just another man (John 6:42). However, the real purpose for this was so that He could sympathize completely with the "human condition" while demonstrating that obedience to God was still possible in this sinful world (Heb 4:15).

This verse contains many titles that describe the Messiah's nature and authority. First it is foretold that He would become the political ruler of the world, which will happen at His Second Coming. Next He is called the Wonderful Counselor. Throughout His ministry here He counseled people to be obedient to God and have faith in Him. The result of this wonderful counsel is that our sins would be forgiven and we could be assured of our place in God's presence forever. Next, He is called the Mighty God. As mentioned above, Jesus was born a human, but He is indeed God. This section could involve a discussion of the Trilogy, but I will save that for elsewhere. Next He is called the Eternal Father. The paradox is that He was born a son, but in fact He was the Father of all. This harkens back to the Creation of the world (Gen 1, John 1:1-5). Another paradox is that even though He was killed by crucifixion, He rose again to demonstrate His eternal power and authority. Finally He is called the Prince of Peace. At the time of His Second Coming, Jesus will destroy the power of sin and death. Everything evil will be confined to some location we know as hell. Thus, those who live in God's kingdom will be free from sin, pain, death, and anything distressing. We will instead enjoy the full goodness and peace of God.

7 Jesus is the rightful heir to the throne of David and will exercise His full authority when the time is right. Currently, Jesus is the perfect spiritual king over those who believe in Him. When He comes again He will demonstrate that He is the perfect political king as well. He is just and will do what is right. He will also be the last and eternal ruler over all people.