No, nothing close to it. They paid 94% in marginal taxes. For example, suppose you make $250,000/year (this put you in the highest income tax bracket through WWII, though it was in the millions shortly before that). Income taxes are calculated in levels, so, creating a totally imaginary tax code, your first $10,000 could be untaxed, the next $20K at 20% ($4000), the next 20K after that at 25% ($5000), the next 50K after that at 40% ($20000), the next 50K after that at 70% ($35000), and everything over $200K at 90% ($45000).
In this scheme, you’ve paid $100000 on $250000 in income, so you have an effective tax rate of 40%, which is pretty high but nowhere near the 90% you would hear people bitching about (the tax laws were actually structured so that nobody had an effective tax rate higher than 77%).
This way, nobody is penalized for making more money and jumping to a higher tax bracket (the “make-one-dollar-lose-five-thousand” argument from people who don’t understand math). It just gets slower-going the higher you get. You have the right to eat regularly, the logic goes, and government won’t take food from your mouth, but you don’t necessarily have the right to eat filet mignon regularly, and the government is going to make you work a lot harder for that.
I think I have the actual tables on another computer somewhere if you’re really interested.