Do 8 reps of squats build leg size?
You can build muscle using any rep range between 4–30 as long as effort and training volume are the same.
Pick a rep range that feels good for you for a given exercise, then train hard.
The squat itself is likely to build leg size. However, for some it will be more hip dominant. And therefore they'd have less quad development than someone with a knee dominant squat.
So. Yes 8 (hard reps) of squats is likely to build leg size.