Oranges and bananas contain natural sugar and is okay for diabetics to eat in moderation.
Just don't over indulge in the oranges or bananas or other fruits otherwise it could spike your blood sugar levels even though it's a natural sugar.
The oranges and bananas are good for you too and provide you with vitamins and potassium from the bananas.
So remember since fruits including bananas and oranges contain carbs and natural sugar they can still spike your blood sugar level but in moderation they're okay but keep check on your blood sugar levels often as well.