You can use my tool for ID verification.
Just write down the ID and add any number to make it 9 digits.
It will tell you that the checksum is wrong and which correct number is expected at the end. (unless you guess the right one)
🆔 Verify Taiwan ID | Project | slawa.dev
Back then they probably did not have a check number, which today is used to make a basic sanity check to weed out random made up ID numbers.