From Pluto, the Sun is fainter than it is from Earth, but still can be 250 times brighter than the full Moon. If our solar system was scaled down so the sun was 1 metre in diameter, Pluto would be 4.2km away and 1.7mm in diameter. 

Pluto travels in a rather elliptical orbit; its distance from the Sun varies between approx. 30 to 50 astronomical units (1 AU is the distance between the Earth and the Sun).

So the size (apparent diameter) of the Sun will vary between 1/30th and 1/50th its apparent size as seen from the Earth. Its brightness would be proportional to the inverse square of distance, so it will be between 1/900th to 1/2500th the brightness as seen from the Earth.

This corresponds to an apparent magnitude of -19.6 to -18.5 in units astronomers use (the more negative the apparent magnitude is, the brighter the object; the Sun, as seen from the Earth, has an apparent magnitude of -26.7.)

This is still significantly brighter than the Moon, which has an apparent magnitude of -12.7. Which, of course, is much brighter than the brightest star in the sky, Sirius, with an apparent magnitude of -1.5.

Jupiter and Venus would look much fainter from Pluto than from the Earth, due to the much greater distance. So the brightest “star” in the sky would, in fact, be Sirius, not a planet. Moreover Venus, even Jupiter, would appear quite close to the Sun as seen from Pluto, so at least Venus would probably be lost in the glare as seen by the naked eye.