We did ours through concierge last year, and had a 3 month old and 6 month old, and they told us they would count as people. For seating purposes only, I don't mean that we had to pay anything for them.
Yeah, they need to be counted, but like the above poster said, make sure to tell them so they dont charge you a deposit on them when you reserve. I guess you will be a party of 9...I think they are free to eat if they are under 3...Can't remember, and our son was 16 months when we went last and I know we didn't have to pay for him.