Jiko is a bit formal for young children (and pricey) so I'd recommend Boma which is buffet style. It's located in Jambo house, the original AKL resort. If you walk through the grand lobby in Jambo and out the back you can wander around the Arusha overlook and see the animals on Arusha savannah. You can also go out by the pool and see animals on Uzima savanah - that's where they have a cm w/ night vision goggles after dark. The gift shop is also worth spending a little time in, I think it's more interesting than many resort shops.
Another option would be to eat lunch or dinner at Sanaa, which is located in Kidani, the nearby DVC building. The lobby is not as grand as Jambo, but Sanaa fronts the Sunset savannah, and it's so cool to look through the windows onto the savannah while you're eating. There's also rocking chairs @ Kidani where you can sit and gaze at the animals on Sunset savannah.
You can easily visit both, say, stop @ Kidani and look at animals from their overlook, and then walk or ride the bus from Kidani to Jambo and look at the animals on Arusha, have dinner, then after dinner go out by the pool to try the night vision viewing.
