If this is a stonesinger, does that mean it likes rock music?
Jokes aside, I actually really like this monster! It's got an uncanny design that in my opinion shows what an aberration should be like, it is truly weird to interact with, and it's got cool special abilities. The only remaining question: does it make a good PC?
Sadly, nine aberration HD make me think the answer to that is going to be 'no'. Large size is decent, the ability scores are decent (20 strength, 18 constitution and charisma, 16 intelligence, 10 wisdom and dexterity), DR 5/magic is kinda meh. The critter has various movement modes, but they're all on the slow side.
In terms of natural attacks, it has six 1d6 claws and a 2d6 bite. The bite also injects a very interesting poison that deals low dexterity damage but completely fossilizes creatures reduced to 0 dex by it. It's not too useful on a PC, but nothing if not flavorful.
Next is Shattering Shriek, which lets the stonesinger deal 12d6 nonlethal damage by making a Perform(Sing) check that exceeds the target's touch AC (apparently, being nimble allows you to dodge sound in D&D). If the target fails a saving throw, it's also stunned for 1d6 rounds, making this a decent save-or-suck. Sadly, its use is limited to once every 5 rounds.
The stonesinger's SLAs are reasonable. 3/day Meld Into Stone and Stone Shape have their uses, and 1/day Wall of Stone is pretty great BFC.
Overall, I'm just not sure this is worth +0 LA. Maybe it if had a few less RHD, or a somewhat better chassis, it'd be worth it, but right now I feel like this monster is just a poor attempt at a BFC caster.