one of my family kid is 15 months old...but he is not stand and move properly and his current weight 9 kg...I am worried about this

A. 15 months baby average weight is 10 kg, baby must have enough strength in muscles to stand and try to walk. Not to worry, the baby will stand on osn within few months. If you are interested to carry out, better to buy a plastic tri wheeler for the child. With your family members supoort you can try this.