You cannot force creativity, and you cannot schedule it.
And you cannot define it. One creative person can do a perfect one-handed cartwheel but another creative person cannot walk across the room without tripping on something invisible. One can make a twelve layer cake, and another can't make a sandwich. Creativity is seeing something (a motor, an egg, a piece of paper, a leaf, a toy, a piece of fabric, some scrap metal) and imagining a different use for it, a different way of presenting it, or how to turn something into something else entirely.
Do your kids eat breakfast? Do they grab an energy bar, or pour a bowl of cereal? Can they make a smoothie out of some fruit and some yogurt? Can they make a pancake, and then return the kitchen to its original clean state? Can they make lunch besides slapping peanut butter on some bread? Do they like cookies? Can they make cookies and come up with fun ingredients (substituting a favorite candy, chopped up, for chocolate chips, for example)? If you prepare breakfast, or set out cereal, maybe you could cook something with them - cinnamon rolls, doughnuts, smoothies, yogurt parfaits, or oatmeal with interesting things mixed in. Get them some kid-friendly cookbooks and stock your pantry with the basics.
Have you ever sat down and really evaluated your kids, by just quietly thinking about what kind of kids they are? Does one of them pair interesting clothing together in wild color combinations? Does one hum along with any song on the radio, in the right key and tempo? Does one mix weird stuff into yogurt and enjoy it? Does one enjoy jumping on a trampoline or dribbling a basketball? Does one like looking at bugs or lizards or flowers? Does one try to plant seeds or keep trying to figure out what's in the middle of an apple or a dragonfruit?
Your children might be very creative, but it might be something you don't recognize. Their strengths may be in an area you never dreamed of. Sometimes we get so busy making sure our kids eat their vegetables and get to school on time and have clean clothes on that we don't stop to really look at them objectively, in order to appreciate what they are really like. And their strengths might not look anything like anything you ever imagined.
Don't try to schedule their freedom to create. And don't label it. Help them to listen to their own hearts and spirits, without your directing it.