This problem relates to IE9 & below

Should I use html5 placeholders or not? We have validation in place and when the zip code reads the placeholder we get an error message, saying it is not a valid zip code. Also in the password field IE9 & below reads as password and creates a user account with that as the password - if the user does not enter one.

Question:
Can I use placeholders without having the issues above and can you show the solution, or should I just go a different route and not use placeholders at all and in that case what is the solution?

Thank you for your help.