I honestly don't recall where I've ever seen that Bruce Banner was Jewish. I've don't recall anything about his faith being mentioned.According to my comic book nerd friend, Bruce Banner is also Jewish in the comics but never in the movies. But that’s normal, right?
It would be normal though, to instead make it part of a character in the movies. In the comics details like religion are kind of side stepped unless it's an important part of the make up of a character. Such as Matt Murdock / Daredevil having his faith / Christianity brought more to the forefront in the last few years, which helps guide his decisions at times. Ethnicity is also something that isn't focused on, unless it's important part of the character. Pretty much nationality, race, & sex have been the biggest defining things about characters until the success of movies. For my comic book days it was Kitty Pride of the X - Men who made a big splash with being Jewish, so for myself she & Ben Grimm are the characters I think of as being Jewish.