I believe several filled markers, which you can specify directly on the symbol statement's "value=" are being added in v9.3, such that you could specify
something like ...
symbol1 v=diamondfilled h=7pct c=red;
But, in the meantime, you can specify any font character that you might have
access to (especially in v9.2 sas, which also supports unicode characters).
Here is an example, using a solid diamond from the Windows Wingdings font,
(character '75'-hex) for example.