What is a "son"?
In the genealogy of Joseph in Luke 3:38, Adam is described as the "son of God" because he was directly created by God.
In like manner, God is the progenitor of all angels. (They are non-procreating beings according to Matthew 22:30.) Thus as beings who are created directly by God, they are "sons of God."
Thus the "sons of God" shouted for joy at the creation of the earth (Job 38:2). These "sons of God" were angels, who like Adam were created directly by God. If we look at all the verses in Job Chapter 38, they are written in two-sentence parallels. That is, the first clause of each verse is modified and amplified by the second clause in each verse. So "sons of God" (verse 7b) are in parallel to "morning stars" (verse 7a), and thus refer to the same thing (i.e., angels).
Now what are "morning stars"?
Morning stars herald the day. That is, they precede the glory of the day. They appear in the dawn, and then, wham!, the full glory of the sun appears. We can say that "morning stars" are therefore the harbingers (or messengers) of light.
The name "Lucifer" means harbinger (or messenger) of light. (In the NASB translation of Isaiah 14:12 he is called "Star of the Morning, Son of the Dawn.") If this character is the "Leviathan" of Job 3:8, who cursed the day by creating darkness (and therefore blighting the morning stars), then he is Satan. (Please click here for an amplification and explication.) He was "created" (Ez 28:13) and therefore was a "son of God."
In Job 1:6, Satan was among the "sons of God" who presented themselves before the Lord God, and again he makes his appearance in Job 2:1 when the "sons of God" again appear before the Lord God. Angels are "sons of God" not because they are good and noble, but because they are directly created by God. Even in the human realm, not all "sons" are benevolent beings like their progenitors (parents).
So angels were created by the direct hand of God, and therefore are "sons of God" (whether or not some of the fell did not change their status as "sons"). When they were created, they were the harbingers (or messengers) of light. (The word "angel" literally means "messenger.") What are they messengers of? They are the morning stars or the harbingers of light, and thus they were intended as created beings.
[Jesus the Nazarene was the Eternal Life, who was robed in human flesh. Since his eternal life stemmed from his father, he was not created like the angels, but born, because his eternal life never had a beginning even though we can still say that he was born. He was born twice: first, he was the first-born of all creation (Col 1:15), which means that his existence existed before anything was created, and so his being stemmed, or was sired, by The Eternal Self-Existing One (אֶהְיֶה אֲשֶׁר אֶהְיֶה); and secondly, he was born in Bethlehem, when his eternal person took on human nature, and so had become robed in human flesh. In this sense he was both the "son of man" and the "son of God" because he was temporally born from a woman (human nature => second birth) and was eternally born from his father (divine nature => first birth). So at his second birth in Bethlehem, he was still one person, but now with two natures instead of one.]
So Jesus the Christ too is a "morning star," because he is THE son of God, and so he is described in Revelation 22:16. This verse in Revelation brings us back to Luke 1:78-79, which in turns draws us back into the Hebrew Bible to Isaiah Chapter 60 in its entirety. For example, the first verses in this chapter in Isaiah begin as follows:
1 Arise, shine; for your light has come,
And the glory of the Lord has risen upon you.
2 “For behold, darkness will cover the earth
And deep darkness the peoples;
But the Lord will rise upon you
And His glory will appear upon you.
3 “Nations will come to your light,
And kings to the brightness of your rising.”
In other words, Jesus the Christ will inaugurate the daylight portion of the Day of the Lord. (The nighttime portion will be the darkness that precedes, since the biblical "day" officially starts at nighttime.) The morning star will be the harbinger, who will inaugurate the light part of the Day of the Lord, and therefore he will terminate the darkness part (which is a time of terrible judgment).
Thus, when Peter says that this "morning star" will rise in our hearts (2 Pe 1:19) he is referring to this time when we will see the daylight part of the Day of the Lord, which is described in the entirety of Isaiah Chapter 60 (among other passages of Scripture). In fact, Peter mentions in the preceding two verses (2 Pe 1:17-18) that Jesus was identified by the voice from heaven as the "son of God," and therefore the "morning star" is to appear through us. (The reason that we as Christians are "sons of God" is because we are born again with the eternal life of Jesus. It is his eternal life that we have as a gift according to Romans 6:23.) We are therefore members of the body of Christ, and so the "morning star" will rise in our hearts as a body of Christ collective.
Finally, there is an aspect of glory associated with the concept of the morning star, and this glory is the authority of rulership (Rev 2:26-28). Jesus was crowned with the glory of rulership (see Ps 8:3-8 compared with Heb 2:6-8). God's glory is his power and authority (e.g., 1 Cor 11:7; Ju 1:25; Rev 18:1). Jesus shares his glory and his power with the members of his Body, and therefore he offers to those who are faithful the power and rulership in His coming Kingdom (Rev 2:26-28). So the term "morning star" captures more than the one who is the harbinger of light, but one who is actually exercising the power and authority of the Lord God (e.g., 1 Cor 11:7; Ju 1:25; Rev 18:1). Jesus was alluding to this glory and authority aspect, when he told the Pharisees that he was God's son (John 10:34). That is, he was referencing Psalm 82:6, which describes the glory and authority of God on earth -- and interestingly enough (again!) there is the imagery of darkness and the shaking of the foundations of the earth and the fallen prince, which hearkens us back to the fallen "morning star".......
Finally, and not least, in this future kingdom (i.e., the daylight portion of the Day of the Lord), the (good) angels will no longer have the front place of exercising the power and authority of the glory of God (Heb 2:5) but all these angels will take second place to the Body of Christ (1 Cor 6:3).