Kong Genius Leo, Small (Color May Vary)

I have a 10 pounder, loves chewing but has little teeth that don't really cause damage. Would any small dog owners recommend this

Is this all three toys?

how big should the pieces be that you use to fill it? My dog couldn't get them out and she's usually really good at puzzles like this.

two different dimensions in description. which is accurate 6 inches or 9 inches?