If you really want to beat Yozora super-easily, restart the game with most of the EZ Codes enabled and play through it until you get to Yozora, then defeat him with one hit. If you want to beat him more honestly, or with some Pro Codes enabled, I have a guide to beat him and other merit bosses with Pro Codes at
Solution for Risk-taker In KINGDOM HEARTS III . If you can't be bothered to read such a long guide, know that the few times I did defeat Yozora without EZ Codes, I couldn't have done it without copious use of Simba's King's Flare and plenty of MP Haste items like Classic Tone and Crystal Regalia to recharge his Link.