8.7 kg is definitely  less for age .u must give 4 to 5 meals a day ,breakfast lunch dinner snack and 1 to 2 fruit servings . Home made food is preferred, make it more calorie dense by adding ghee,jaggery ,potato,yam U may give boiled sprouts,veggie khichad,dal rice, roti dal,curds ,idli etc .eggs,non veg also ok At this age everything  is preferred, make variety,colored veggies ,ghee,nuts .