how to calculate the score

in this position,  why the score is +8 and not +9? thanks!

Ah ok, I knew she was 10....

They didn’t rate her a 10 because she was overly aggressive.

What do you mean?

the opponent has an extra pawn

Of corse, he has... but what does it mean that my queen is overly aggressive... maybe i dont understand the traslation in italian....

Sorry, it was just a joke. Yes, a queen is worth 9 points, not 10.

Ok thanks to all!

Black has captured 9 points of White's Material
Pawn - One Point Each 
Minor Piece (Bishop/Knights) - Three Points Each
(3x1) + (2x3)
White has captured 17 points of Black's Material
Pawn - 1 Point Each
Minor Piece (Bishop/Knights) - Three Points Each
Queen - 9 points each
(2x1) + (2x3) + (1x9)
17 - 9 = 8

You had a bishop for a bishop (equal) a knight for a bishop (equal), and an extra queen (+9), but you had one pawn less than your opponent, and 9-1=8. Hope that's helpful.

yes ok... I knew the queen was 10, but I was wrong.