If you decide to buy a kitten, browse to Sale conditions. The status, stated in a kitten's profile, means the following:

for sale – a kitten is available and you can buy it or pay a deposit
cattery supervision – probably a kitten will be available later
reserved – a deposit for a kitten has been already paid
sold – a kitten left the cattery

On the page Plans you can get to know about newborn kittens under the age of reservation, expected litters and matings.