There were 30 + 20 = <<30+20=50>>50 attendees at the party.
A total of 50 x 2/5 = <<50*2/5=20>>20 people left the party.
Nine of those who left were men while 20 - 9 = <<20-9=11>>11 of them were women.
So, 30 - 11= <<30-11=19>>19 women stayed at the party.
And 20 - 9 = <<20-9=11>>11 men stayed at the party.
Thus, 19 - 11 = <<19-11=8>>8 more women than men stayed at the party.
#### 8