are you just trying to make the program stay in a loop, incrementing and displaying A via interrupt until (9) is pressed?
if so, you should do this:
:.A
:1->AFnInt(GO,6
:FnOn
:Repeat getkey(9)
:Pause 3 //im not entirely sure why this has to be here, but it does(only if you're doing a repeat loop with end immediately afterwards, though). ask quigibo
:End
:LnReg
:Return
:Lbl GO
:A+1->ADisp A▶Dec, i
does help?