Canvas draw does not support the Unicode based characters, so the symbol font in OSX will not work in Canvas draw.
As a workaround, if you need to create document with the Greek symbols, you can try following to install one of the following two fonts.
1) Naxos (a sans-serif font, with regular, bold, italic, and bold italic versions)
2) Eisago Greek (a serif font, no true bold or italic versions).
After downloading the fonts, copy them to the System Font folder - Macintosh HD\Library\Fonts. Close and then restart Canvas draw, and you will see that Greek font will become available in Canvas Draw's font menu.
Please note the following limitations with this workaround:
1) Installation the font will not convert Symbol font you used in the previous version of the Canvas document.
2) If you need to open the same Canvas document in a different machine Canvas draw for Mac, or Canvas for Windows is installed, you will need to install that same Font in order to recognize those fonts.