Every site will tell you it's supposed to be firm, but crumble when you touch it. In my experience, that's rarely the case.
All my cats have either had too runny or too hard stool, and it was completely dependent on what I was feeding them.
As I recall, my cats are the same age as yours. Mine use the litter, and they almost sit as they are defecating, so it's really hard to tell if it's runny or not because they smush it all over themselves.
But, from what I've found, it really doesn't matter as long as it's not abnormal poop. By abnormal, I mean cottage cheesey or bloody (which one of my cats had at one point...I don't know how the runt of this litter has stayed alive).
I wouldn't worry about it too much. If you get concerned, just make sure Peanut is hydrated. When all four of my cats (very messy week) had explosive diarrhea, I gave them pedialyte instead of water in their formula to make sure they stayed hydrated. You can do that if it persists.