If you read the first section - 29.1 Applicability - you will see that the references to 20,000 lb are only pertinent to the requirement to be certified as Category A or not.
CS29 most definitely applies to aircraft above 7000 lb.
On a pedantic note, should not the following:
Rotorcraft with a maximum weight of
9072 kg (20 000 pounds) or less and nine or
less passenger seats may be type certificated as
Category B rotorcraft.
say "..nine or
fewer passenger seats.." ?
