;-------------------------------------------------------------------
;Victory screen definition
;This is the screen that is shown when you win a match in arcade mode.
;It will not be displayed on the last match of arcade mode.
[Victory Screen]
enabled = 1
time = 300                ;Time to show screen
fadein.time = 8
fadeout.time = 15
;Winner's portrait and name
p1.offset = 200,20
p1.spr = 9000,3
p1.facing = 1
p1.scale = 1,1
;p1.window = 0,0, 1279,500
p1.name.offset = 75,375 
p1.name.font = 1,0,1
;Win quote text
winquote.text = "Winner!" ;Default win quote text to show
winquote.offset = 75,400
winquote.font = 2,0,1
winquote.window =  0,100, 600,480 ;400,300
winquote.textwrap = w     ;Word wrap

Victory screen will default to 9000,1 if you don't have anything in 9000,3. You should confirm that's what Mugen is doing through the Debug.

If I recall correctly 9000,3 is not a valid portrait and that's why you are getting the default. Only 9000,1 and 9000,2 are valid.  there is work around's you can do to add more portraits, that requires a portrait templates and positioning of your sprites to allow them to display, here is an example if it makes any sense.

Outdated portrait template: I can't give you the exact axis since I'm at my work pc, but a quick breakdown of it is positioning your portrait at the right axis for them to display in your versus screen and in your winner screen since the 9000,2 portrait will be shared.

Spoiler, click to toggle visibilty

You my friend you're now doing like me for portraits, right?

Hold up.  There's an option to change the victory screen portrait from the default of 9000,2, yet it doesn't actually work and it'll still check for 9000,2 anyway?