At Keio Line's Kichijoji Station, there's only one ticket gate. When you exit the gate, you'll find escalators directly in front of you, a Starbucks Coffee on your left, and KIRARINA on your right.
And, near the entrance of Starbucks Coffee on the left, there's a seating area where you can take a break.
There are four wooden benches set up here.
Because it's right in front of the ticket gates, there's a lot of foot traffic, but it's easy to find, making it a great meeting spot in Kichijoji.
Since the benches are outside the ticket gates, you can use them by going up the escalator from the JR line ticket gates towards the Keio line ticket gates.
Regarding congestion, I checked on a weekend evening and found that there were 3 people using it.
However, it seemed like people were coming and going quickly, so it's unlikely you'll have trouble finding a seat.
Also, it's indoors, but there's no air conditioning, so the comfort level might drop depending on the season.
If you're looking for another meeting spot in Kichijoji, I also recommend the indoor "4F KIRARINA Plaza"!
Why not give this seating area a try as a place to take a break around Kichijoji Station?