Car seat question!!

I just got the graco extend2fit which we love already!! but as far as the recline indicator goes im a little confused! my baby is 8 months old so he doesn’t have to go in the light blue circle but I feel like he’s a little uncomfortable sitting that straight up for now and being halfway in light blue/half in dark would be better for him but I don’t want to do anything unsafe?

added the manual it isn’t specified