The word Heylel means light bearer, he was not the light he was just a carrier (bearer) of the light...
Both
heylel and
lucifer refer to the planet Venus. The third brightest object in the night sky, Venus has been known for thousands of years as the "morning star". It is known as the "light bringer" because it is a harbinger of dawn. Because of the planet's position in the solar system, it can only be seen low on the horizon three hours or less before sunrise or after sunset. Thus, when it appears in the morning it is the herald of dawn... the brightest object in the sky besides the moon, when it appears in the morning it signals that dawn is not far behind. Thus... it is called the day star, morning star, and "light bringer".
The Latin word 'lucifer' historical referred to the morning star (aka Venus). It meant the morning star at the time it was first used in the Vulgate and it meant it at the time the KJV was translated. There are a plethora of historical literary references in which people used the word 'lucifer' to describe the "morning star".
For instance, in the Vulgate (from which the KJV picked up the word) the word 'lucifer' is used several times, none of them referring to Satan (i.e. Job 11:17 & 38:32; Psalm 109(110):3; 2 Peter 1:19).
So, basically, the English versions that use the words "morning star" have done nothing more than translate "lucifer" from Latin into English.
We could just as easily translate the passage by using the word "Venus" (in order to refer to the 'morning star' by the most commonly used name for that celestial body in our modern usage). However, it would lead to confusion, because then people might think the passage was referring to the ancient mythological god. That's basically what using the word 'lucifer' was all about - it refers to that actual, physical star that appears in the sky in the morning.
Metaphorically and figuratively, Jesus (and others) have been compared to that star.
The words morning star are not in that verse, the literal translation is son of the dawn, not morning star... the dawn is not the light but a pale reflection of the light...
You are conflating two terms. 'Morning star' and 'son of the morning' are both in the passage.
heylel = lucifer = morning star or light bearer/bringer
ben shachar = son of the morning
Both terms (heylel and ben shachar) appear in the verse. Heylel's translation is not "son of the morning".
Where is Satan called a lion?
1 Peter 5:8
For a very in-depth study of this issue, I encourage everyone who is interested to check out this site:
http://www.kjv-only.com/isa14_12.html