Hi Kim!
Welcome back! It's always a pleasure to help out a returning Guest. I hope you have the BEST TRIP EVER with your grandson in just a few weeks. I used to travel with my grandparents yearly to the Most Magical Place on Earth and I have so many special memories from those trips. I hope you make many memories together that you will cherish for a lifetime.
You certainly can get a birthday cake to celebrate your little prince and his big ninth birthday, in fact Disney has many ways to
customize your celebration. You have 2 options for cakes. The first option is to have a speciality cake created for your grandson. You could customize this cake with his favorite characters and make it truly one of a kind. The number you would need to call to place a specialty cake order is ( 407) 827-2253. Please order this cake at least 72 hours before your celebratory meal in order for the chef to make it super spectacular.
A second cake option is to request a 6 inch Celebrate Today! cake upon arrival at most table-service restaurants. These cakes come in both chocolate and vanilla. They will not be as elaborate as a specialty cake, but they do not require a pre-order. Just inquire with the Cast Member at the host stand when you arrive for your meal.
Most restaurants will acknowledge a birthday celebration in some way. I advise you to call and have your birthday celebration added to your existing dining plans. You never know what sort of pixie-dusted surprised may fall upon your grandson. Also make sure he gets his complimentary 'Happy Birthday' button from any Guest Service location on property. It's sure to bring lots of well wishes his way.
Thanks for stopping by! Please wish your grandson a very happy birthday from the Disney Parks Moms Panel.
~Jen