Jupiter is the easiest planet to observe in the Solar System and the one that is the most interesting. It’s 4 Galilean Moons, The Great Red Spot, and cloud bendings are all observable with NexStar 6SE optics. The unique beige-brown-red colors of the clouds are clear.
Saturn shows its unique yellow-green color, and its rings are clear with The Cassini Division in the middle. Its moons are visible, but Titan, the largest one, is the one you will most likely be able to observe.
Mars and Venus are harder to gather detail from. They are rocky planets and not gas giants. The surface details on Mars is visible as black-red-white stains, and Venus looks like a yellow disk. Phases of Venus are observable.
Uranus, Neptune, Mercury, and Pluto are challenging to observe with any telescope. Although you can obtain Neptune and Uranus’s blueish colors, Mercury and Pluto look like dots most of the time.