Yes, DESTINY is a Scrabble word!

Letter values in Scrabble US: D 2, E 1, S 1, T 1, I 1, N 1, Y 4.

Is it a valid word?

DESTINY is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an event (or a course of events) that will inevitably happen in the future
the ultimate agency regarded as predetermining the course of events (often personified as a woman)
your overall circumstances or condition in life (including everything that happens to you)