Hard to tell.
There's a difference between destroying the moon and vaporising the moon.
When Piccolo fought Raditz he had a weighed PL of 322 and an unweighted PL of 408. Freiza tells us that removing weighted clothes only makes you faster, not stronger, so while Piccolo measured in at 322, his Ki blasts would be that of a person with a PL of 408.
When Piccolo vaporised the moon, his weighted PL was measured at 329, not 322. That means his ki blasting PL was more likely to be something like 415. But for the sake of argument, its at least 408.
If you take a proportion based on Mass, the Earth would take a PL of 33,158 to vaporise.
Vegeta had a power level of between 18,000 and 24,000 when he attacked Earth. We know the last time he saw Cui, he had a power level of 18,000, but Vegeta told him that he'd been constantly fighting and getting stronger since then, he didn't only attack Earth.
When Goku was measured by Nappa after powering up, he said Goku's PL was over 8,000. We dont know by how much, but when Goku faced Vegeta with a Kamehameha, Vegeta said was the same as his Gallic Gun. Essentially, they're the same energy attack. Thats an important thing to note because when Goku went Kaiokenx3 with that Kamehameha, he and Vegetas Gallic Gun were equal. That means Vegeta's powerlevel wasnt 18,000 as is often suggeted, its much closer to 24,000.
So the question is, if it takes a PL of 33,158 to vaporise the Earth, would a PL of 24,000 be enough to destroy it? Well at 72% of the vaporisation energy, I would say yes, of course it would be. Especially when you take into consideration that Piccolo may not have needed all of his power to have destroyed the moon anyway.
So if it takes a PL of 408 to vaporise the moon and 33,158 to vaporise the Earth, how much would it need to destroy the Sun?
The Answer would be 11,038,481,616.
The sun accounts for 99.86% of the mass of the whole solar system, which means for Cell to be able to destroy the Solar System, he'd need a power level of at least 11,053,957,156, which is 73.69x more powerful that Goku when he first became a Super Saiyan.
I dont know about you, but to me that sounds about right, although Id be willing to bet that if Toriyama did those calcs, and I think he probably did, he'd use nicer numbers, like Cell having a PL of 11,250,000,000 which is 75x as powerful as Freiza saga SS Goku.
If I'm right, this would be your list for our Solar System
|Celestial Body||Mass (x10^22)|
|Ki for |
For reference, the Milky Way would need a PL of about 2,207,800,000,000,000,000,000,000, or 2.2 Septillion.
The Visible Universe as we know and understand it would need a PL of something like 1,103,900,000,000,000,000,000,000,000,000,000,000,000,000,000,000. Or 1.1 Quindecillion.
Which means that since Zeno destroyed the multiverse, he's at least 12x that powerful with a PL equivalent to 13.25 Quindecillion.