The 20MP sensor on the Hero 9 almost doubles the pixel count of the Hero 8 at 12MP. If you want a bump in resolution to 5K and the slightly longer battery time, the Hero 9 will be the better option. The GoPro Hero 9 was released in 2020. Since then, two more GoPro Heros have come out. The Hero 8 was the predecessor to the Hero 9, which came out LdXC.