I agree that this is a very difficult topic to research since there has been misinformation going around for hundreds of years now! 
The etymology of lucifer shows that it’s a Latin word from lucis, “light” and ferre, “to bear” – literally lightbearer.
The lightbearer was Venus (the planet) the morning star which anounces the sunrise. 
Here’s an explanation:
“Lightbearer” has its first religious root in the Hebrew phrase “Heylel ben Shachar” in passage 14:12 of the Book of Isaiah in the Old Testament, meaning “son of the morning star”. In this passage Isaiah is alluding to the pride of the Babylonian king Nebuchadnezzar II - prophesying his eventual fall by referencing mythological accounts of the planet Venus.
From: https://www.scienceofbeing.com/lightbearer-meaning
Although today Biblical scholars agree that Isaiah was referring to the Babylonian king, misinterpretations of the Biblical text, starting with St. Jerome’s Vulgate Latin translation in the early 5th century and poetic associations in Dante’s Inferno and Milton’s Paradise Lost, has led to the common Christian belief that lucifer in this instance is a reference to the satan myth of the fallen angel instead.
In short, Lucifer was never a historical being, not a god or deity of any kind. Simply a mistranslation.
Eventually it became a movement. Lucifer the Lightbearer was an individualist anarchist journal published in the United States by Moses Harman in the late 19th and early 20th centuries. You can read more about this movement here: Luciferianism.