Mercury and Venus are blank crescent or gibbous orbs, with no discernable features – Mercury lacks any large, contrasting details and Venus’ surface is of course obscured by clouds.
The Moon is dazzlingly bright (though still harmless) and shows details under a mile across on a still night with good seeing.
Mars’ polar ice cap and a few dark markings should be obvious when the planet is close to Earth. Its moons can also be glimpsed with careful observing techniques, and any dust storms should be immediately apparent as they obscure all other surface details.
Jupiter’s cloud belts are vibrant and explode with color, and the Great Red Spot is easy to see. Jupiter’s 4 large Galilean moons all appear as disks with good seeing, and their shadows can be seen on Jupiter’s cloud tops when they transit. Ganymede may show a surface detail (a brown northern hemispheric feature called Galileo Regio) the other moons are noticeably not uniform bright balls with good seeing.
Saturn’s rings are gorgeous, and the Cassini Division in them is usually apparent. On a very good night the Encke gap in the rings can also be seen. More than half a dozen moons are visible, along with cloud belts on Saturn itself.
Uranus’ featureless disk can be resolved with the C11, and a few of its moons are faintly visible (glare from Uranus itself can make it difficult).
Neptune is a bluish star-like dot, but its moon Triton is fairly easy to see.
Pluto can be seen as a star-like dot under dark skies if you can figure out which one of the hundreds of points of light in your field of view it is.