Can a planet with a dense atmosphere composed mainly of sulfur dioxide have a blue sky like Earth's due to Rayleigh scattering? Or would the composition change the color of the sky? I mean, it's well known that methane is responsible for the bluish colors of the atmospheres of the icy giants of the solar system, Uranus and Neptune, so it's logical to think that a planet with a significant amount of methane in its atmosphere would have a blue-green sky, would the same thing happen in a planet with a dense atmosphere of sulfur dioxide?
Rayleigh Scattering is a universal physical process so it will always be involved when light passes through gases. Which is not to say it will always be the dominant determinant of the color of the sky. But in the case of an atmosphere composed of $SO_2$ that is doesn’t significantly absorb wavelengths shorter than 600 nm, Rayleigh scattering will dominate the color of the sky.
But the efficiency of scattering is proportional to the polarizability of the molecule. $N_2$ and $O_2$ have similar values ~1.6-1.7. $SO_2$ is 3.8
This means that longer wavelengths like green and will scatter more efficiently in your atmosphere than they do in Earth’s atmosphere.
I expect that your sky will be green near the star and then blue green then blues then to violets as you look to the horizon.
Table of Polarization Values for some gases. https://cccbdb.nist.gov/pollistx.asp#1977Mil/Bed:1