This is called the 'vintage style Sonic' backpack. It's a Spencers item in spring/summer 2021. The name for it is both true and not true. It uses all classic style and neoclassic art for the rather busy design, but the look of the bag is not 'vintage' nor 90s at all. Something like this wouldn't be produced then, it is not the style of the time.
The slogans don't help either, with "Gotta Go Fast" which is the meme/gag thing that caught on from the Sonic X anime opening theme song getting made fun of. The bag is white with black trim, straps, handle and zippers. It's a full size bag, probably canvas-type as it is somewhat costly at 50 dollars. It has "Let's Go", "Gotta Go Fast", Sonic's name and Sonic's name spelled out in Japanese (along with 'the hedgehog' also in Japanese) 1991, checkers, pixel rings and an unknown Japanese phrase in red.
The bag is certainly very Sonic, if a tad busy and lively but that's the point. It's a nice item for classics fans.