Guy snitched

First World like problem. Nobody like cares...

Jump him.

You're fine, just tell ur teacher the truth and if they don't believe u, not ur problem. U know what happened and who cares what anyone else says and actually it's not that easy to get put in a care home, they can't just pick u up and put u in one, just chill, it's fine and I'd beat the shi* outta that guy or at the very least have a go at him for it

I just don’t know because there’s no guarantee I won’t go into care

Ur worrying about nothing. There's EVERY guarantee u won't get put into care, don't stress they can't do anything without ur parent's permission. It's okay, u weren't doing anything wrong anyway

Don't worry.
He is just another gossiping student with no evidence and has no way of proving that his claims are true.
In the midst of a pandemic, social services are operating under a lot of pressure and with limited staff coming in to work.
They won't prioritise investigating the uncorroborated claims of a random student from your school who is telling anyone who will listen that he saw you driving around in a car.

If told about his allegations by an adult professional and asked what happened, you just reply that you have no idea what he is talking about.
Only he knows why he has started telling nasty stories about you being a criminal and joyrider.
But keep an eye out for more wild tales, he may start rumours about you being a bank robber or reality tv star.