Checkbox size

PWR wrote:

Changes the text size but not the size of the text box itself

Then no—

If you had a hotlink or a specific example might help decipher a work a round...

Increasing screen resolution is always an option:

>System Preferences>Display

Change your Mac display's resolution - Apple Support

PWR wrote:

Is there a command to resize a Checkbox?

General key short cut for increasing decreasing the interface, try:

Command +

Command -

Command 0 default size

Change the font size or zoom level of web pages in Safari