How have you specified matrice ? If it is a byte sized variable, then your statements should be

btfss _A8
and _matrice+0,w
btfss _A9
and _matrice+1,w

If your variable is a word sized variable, then you need to read/write word sized variables like this

btfss _A8
;; read the word from matrice[0] assuming MSB first (Big endian)
;; movf matrice+0,w
;; movwf TempM ; read the msb
;; movf matrice+1,w
;; movwf TempL ; read the lsb
;; --- now perform the operation you desire here

I hope I have been able to address your query

Jerson