Makena is from the Kikuyu Makena — happy one, one who brings joy. Makena is one of the Kikuyu + Swahili feminine names — central to traditional Kenyan + East African heritage.
Makena 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 Makena reduce to 9, The Giver. This is a traditional interpretive system, not a factual claim about the name.