Quoted from Rav Simcha Bunim Cohen’s sefer “The Three Weeks,Tisha B’av and Other Fasts”,-“Children who have reached the age of understanding the concept of mourning(i.e.,7 or 8)should be trained to wear non-leather shoes on Tisha B’av.However, nowadays the custom is that even children below that age do not wear leather shoes.” The footnote to this states (in translation)”this is the custom everywhere.” AS for hearing Eicha, after you get your kids to sleep and won’t be disturbed,sit on the floor and read it yourself.