Whatever your comfortable with. Unless someone here has had to shoot a charging grizzly with both then all you’re going to get is opinions.
My opinion, someone who has never had to defend myself against a grizzly with anything but have read the one big article about all the different pistols being successfully used in defense against grizzlies and both the 357 and 9mm being used successfully, I’d take the 9mm. I shoot semi auto better than revolvers, myself and everyone else on the planet will put more rounds on target faster with a 9mm than a 357, and the capacity is at least double even if you have an 8 shot revolver, three times as much if it’s a 6 shot and the Glock has flush mags, more than 5 times as much with an extendo. So for me more rounds on target > marginally better penetration.
If you’re not opposed to buying a new gun I don’t think a 10mm would be a bad idea, but you’ll probably be just fine with a 9mm.
I’ve been within a few feet of huge grizzlies in captivity and held a few day old grizzly cub as a volunteer and they’re big motherfuckers but pistols are pistols and the differences are marginal IMO.