U can give 2 times a day U have to give him exercise also with controlling food
Stop giving him rice U can feed him raw vegetables and chapathis, chicken also is fine
The puppy is old enough to be shifted to 2 proper meals and a snack in the afternoon. When feeding home cooked food you should make sure you don't give too much carbs, like rice/ roti/ bread instead feed more protein rice food like chicken/ eggs/ pulses/ paneer/ soya. Also make sure the puppy gets some calcium supplement at least till he/she turns 1 year of age.