From what I understand the word
Lucifer comes from the latin translation. Lucifer meaning Venus.
Venus
Astronomy the second planet from the sun in the solar system, the brightest celestial object after the sun and moon and frequently appearing in the twilight sky as the evening or morning star.
Is it a bad use of the word? Well Christ is also referred to as the
Morning Star - 2 peter 1:19, but the word here is
Phosphoros and the word in Isa 14 is
Heylel.
It is an English translation problem and it is probable that the KJV was trying to keep from using the same English term for both Christ and satan. Some translations use
king of Babylon instead of Lucifer or morning star.