Zoom is a Design View feature only.
Go to Edit > Preferences > Fonts.
Select a Code View font that is bigger than what you use now for Unicode and Western European (if you use that charset). Repeat with any other charsets you use. Hit Save.
To add to Nancy's and for your situation where you don't want to make it bigger, if you're on a Mac, you could use Ctrl + 2 finger scroll feature to Zoom in and out temporarily when required.
Most versions of Windows have a built-in Desktop Magnifier tool, too.
Nancy, I'm DW 9 for Mac, I don't think I can put a signature on this forum anymore correct?
Well, I went in preferences and cannot find where to change the code view font.
S. I'm on a mouse so the two finger thing wont apply I don't think.