I've used children's conditioner before. I have one called CurlyKids Deep Conditioner and I like it. Makes my hair soft. I also use(d) Shea Moisture Kid's Detangling Spray. I really like that one.
Of course you can! Unless it is a shampoo that promises to not burn eyes, or a chemical treatment, the products are the same as the 'adult' formula. The only difference is the marketing of said products.