As long as you're willing to use an adult TS credit, it seems that it is allowed. Just ask - people have reported being able to use adult table service credits to get kids meals. Apparently, some restaurants will increase the quantities of the kids meal to make it more adult proportions. You will find though that most restaurants do offer quite a variety of entrees - and most places are very good at serving sauced food without the sauce (which seems to be the part a lot of kids don't like...they'll eat the grilled chicken breast, just don't want the fancy-schmancy sauce on it.) or allowing plainer subs (like plain mashed potatoes instead of something dripping exotic sauces.)
