There is no longer a Magic Kingdom Card discount on any 1 Day Disneyland Ticket no matter where you purchase it. Discounts still apply on Multi-Day passports, however.

And just FYI, Disneyland has just recently changed the "Child" classification from ages 3-11, to ages 3-9. After nine years of age they are now a full priced "Regular" guest (see how clever they are avoiding the word "Adult").