Can you buy 999 moons in Mario Odyssey?

Excuse me, I'm a bit confused by the question. Are you asking if it's possible to purchase 999 moons, the in-game currency or collectibles from the video game Mario Odyssey? If so, let me clarify that Mario Odyssey is a game for entertainment purposes, and its in-game currency or collectibles, like moons, are not meant to be purchased with real money. Instead, moons are earned through completing challenges, puzzles, and missions within the game. So, in short, no, you cannot buy 999 moons in Mario Odyssey.