The 800 loop is very large and you can be pretty far from the CS and bus stop. Being such a large loop people tend to drive a little too fast at times especially if they have to go all the way around the loop to ge to their site on the other side. We also had our worst experience with biting bugs in the back of the 800 loop. The 900 is much smaller and has a lot less traffic.
Only thing about the 900 loop is if there is a large group of people camping in the primitive campground on the other side of the cannel you can have a lot of foot traffic cutting through the 900 loop on the way to the pool. But this does not happen often and it is just people walking through at regular hours, not a big deal at all.