Bit off topic but there's something I never got quite right in american linguo: do they say people do 9am - 5pm workdays ? Cause in France where I worked 3 year

Bit off topic but there's something I never got quite right in american linguo: do they say people do 9am - 5pm workdays ? Cause in France where I worked 3 years and Hong Kong 7, it's more 8:30-7. Someone leaving at 5 is almost reason for a riot in a team in both countries, how is it so common in the US?