Chaeyoung is from the Korean chae (채 — color, splendor) + young (영 — glory, eternal). Le Sserafim's Chaewon is a different Korean K-pop singer of similar name. Princess Chaeyoung — modern Korean heritage naming.
Chaeyoung does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Chaeyoung reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.