There are a couple of ways.  One is to use a the "Statistics Calculator" Add-In by BradyBrady in the file exchange.
To do so without the calculator you can build a small table:
| Weight | Outcome | Group | 
| 10 | 1 | A | 
| 4 | 0 | A | 
| 9 | 1 | B | 
| 5 | 0 | B | 
Then use fit Y by X with (nominal) Outcome = Y, Group = X, and Weight = Weight.  Under the red triangle menu is the "Two Sample Test for Proportions" (note, this option only appears when you have two groups).