What astronomers are actually counting
When astronomers say a star has "many" or "few" planets, they usually mean planets they can detect, not every planet that exists. The Kepler survey used in one of these studies counts planets with radii at least about that of Earth and orbital periods under 400 days—in other words, planets close enough to their star to cross in front of it and be spotted [3]. That is a narrow slice of a planetary system. A distant giant like Jupiter, orbiting far out and taking years to complete a circuit, would not show up in that count.
With that caveat, the survey result is that about 30% of Sun-like stars host this kind of close-in planet, and each such system averages about three planets within 400 days [3]. The authors note that the Solar System, despite not belonging to this "Kepler club," also has three planets within 400 days, and its planets' orbital tilts are similar to those of Kepler systems with the same number of planets [3]. So by the measure of close-in planet count, the Sun is fairly ordinary.
Why the Sun still looks different from most Kepler systems
The difference is not the number of planets but their arrangement. Kepler systems are typically packed with planets on tight, nearly circular orbits, all huddled close to the star. The Solar System has its small rocky planets close in and its giant planets much farther out, with a big gap in between. That architecture is what makes the Solar System stand apart from the Kepler sample [3].
The same study found a pattern among Kepler systems: the fewer planets a system has, the more spread out and tilted their orbits tend to be—what the authors call being "hotter dynamically" [3]. The Solar System fits that trend in miniature, since its three inner planets have an orbital tilt spread similar to Kepler systems of the same multiplicity [3]. In other words, the Sun's system is not odd in its planet count; it is odd mainly in having giant planets far from the star, which the close-in surveys are not designed to see.
Water and the Sun's interior: other ways our system stands out
Planet count is only one measure of oddity. Earth's surface liquid water is unusual among the terrestrial planets, which generally lack it [2]. One modeling study of Venus and Earth concludes that water-rich asteroids striking these planets could not explain the measured composition of Venus's atmosphere, which implies the material delivered after the giant impact was dry [2]. That in turn suggests Earth's water was present from formation, buried deep enough to survive the impact, and that planets may form with nearly their full water budget and lose it gradually [2]. This is a proposed explanation from models, not a settled fact, but it points to Earth's water as a genuine distinguishing feature of our system.
The Sun itself also carries a faint record of its planets. Models of the Sun's evolution indicate that planet formation happened while the Sun's outer convective layer was still massive, so the compositional changes it caused were too small to explain a long-standing mismatch between solar models and observations [5]. Even so, the models find that planet formation leaves a small imprint in the solar core, raising its metallicity by up to about 5%, a prediction that could be tested by precise measurements of the solar neutrino flux [5]. That is a subtle signature, not evidence that the Sun's planet count is unusual.
So is eight a lot?
The honest answer is that we do not yet know the full planet count for any star other than our own, so comparing total numbers is not possible with current evidence. What the surveys do show is that systems with a few close-in planets are common—about 30% of Sun-like stars have them—and that the Sun's inner system matches that pattern in planet count and orbital tilt [3]. The Sun's system looks distinctive mainly because of its far-flung giant planets and because Earth has liquid water, not because eight is an unusual tally [2][3].
One broader point from the evidence: the Sun's planetary system is described as ending with Mars in one historical discussion of alternative skies, a reminder that how we count "the planets" depends on what we include [1]. That source does not address whether the Sun's planet count is odd, so it offers context rather than a verdict. The weight of the supplied evidence points the same way: the Sun is not strange for having several planets, but it may be unusual in how they are arranged.
Sources used in this answer
Many Skies: Alternative Histories of the Sun, Moon, Planets, and Stars
The paper explores alternative histories of celestial bodies and mentions the Sun's planetary system ending with Mars, but does not address whether the number of planets is unusual.
Late Accretion and the Origin of Water on Terrestrial Planets in the Solar System
Modeling of Venus and Earth suggests late-delivered asteroidal material was dry, implying Earth's water was present from formation and buried deep enough to survive the giant impact.
About 30% of Sun-like Stars Have Kepler-like Planetary Systems: A Study of their Intrinsic Architecture
About 30% of Sun-like stars have close-in Kepler-like planets, such systems average about three planets within 400 days, and the Solar System's three inner planets and orbital tilt spread resemble Kepler systems of the same multiplicity.
Rotating planets in Newtonian gravity
A rotating-planet model fits the shapes and surface velocity fields of bodies from Earth and Mars to Saturn and Haumea using only two parameters, with planetary rings emerging naturally.
Imprint of planet formation in the deep interior of the Sun
Planet formation occurred while the Sun's convective zone was still massive, leaving only a small core metallicity enhancement of up to 5% that could be tested via solar neutrino measurements.