Honestly, I think that would suck quite a bit. I would have the intelligence and experience of an adult trapped in the body of an 8 year old and dependent on my parents. I wouldn't be able to live independently for years. It would also be difficult to speak and act like an 8 year old. I have a university degree and an 8 year old with university level education would probably make me some weird child prodigy. Not only would I be dependent on my parents, but everyone would be pushing for me to be some genius by the time I'm an adult. I'd eventually grow up to be a huge disappointment. So really I'd kind of just be reliving the past!

The only saving grace is that I might be able to make some money off investing in tech companies and crypto before their drastic increase in value. At least I wouldn't need to work my entire life.

Am I eight years old now in 2025, or eight years old way back then?

1985.
It's 4 years before my first D&D game.
3 years before I pick up a guitar.
10 years before I start snowboarding.
20 years before I convince my republican parents there's a better way. 
Suddenly I am fluent in several languages, as if by magic.
I have a grasp on global politics and the knowledge of what's to come.
What do I do?
Play.
All day.
I swim. I run. I bike. I draw. I skate. I be. 

And I plot. 

Go see Star Wars in the theater again. :)

Does my depression also go back in time?

I'd have a serious conversation with my parents about the less obvious symptoms of ADD. (It didn't have an H back then)

Besides that, I often wonder what I would do when I meet my ex wife. Avoiding her would save me trouble down the road, but then my three amazing kids would never exist and if the reset happened tomorrow, I'd have so many unanswered questions of whatever happened to them in that other timeline.

First, I would convince some of those old crazy ass mercenaries that my uncle used to hang out with that Donald Trump touched me. This would be in 1992. Then I'd work my ass off mowing lawns and doing chores and saving every bit of money I could, invest in apple and other big stocks that I could get as they came out before they hit big, id sell them and invest in Tesla before Elon could get in on it, and Bitcoin. Id use my wealth to invest in solar so that it takes off earlier. Create a Superfund to counter lobbyists like the dark roofing lobby. What a completely asinine thing. Just switch to making white roofing materials? Use my wealth and power to become president, reverse citizens United and bring back a 90% tax on the wealthiest people. (Yes, Including myself.) Boom. World saved.

Immediately begin my global takeover. 1983 would never know what was about to happen. By 1990, the world would be mine.

Why 8? I'd be really dependent on my parents again, and it would be impossible to explain my sudden precociousness and knowledge of the future.

Anyway, I'd try to work out and get stronger, and stand up to my bullies. I'd have some choice words for their sorry asses.

Just kill myself and prevent the worst of it.

The real question, I guess, would be how to strike out on my own as a literal child. School was repetitive the first time, and my home life was pretty mid as well.

Funny story, I think I actually had enough savings at that point to live on for a month or two. I was a weird kid.

Go to the library a lot. Learn and master the art of lock picking. Make more friends at school (networking). Wear crocs way before they’re cool.

Hold on! Can I still do some research before this happens?

One thing I'd do for sure is, transfer to a different primary school. A better one. I just don't know which one, not even now.

Anyway, a 166 MHz Celeron CPU and 32 MB of RAM aren't very performant, most likely I won't do anything insane with it. I won't be able to write Rust applications, as a Rust compiler wouldn't exist yet. Also, my HTML5 knowledge wouldn't be usable either. I'd have to descend to XHTML strict standard, and CSS will be a pain in the ass once again.

I'm just realizing, I wouldn't be able to do much with my current knowledge.

Education and hard work, these are the two things I'd pursue at all costs. One of the biggest fuck-up of my life was at age 6, but it could be still corrected at age 8.

I'd spend a lot of its mourning that I'd never be able to replicate my daughter as she is now. I could time it right to get the right egg, but how many wanks, exactly, and when did I have? How could I possibly even guarantee the right sperm even if I manage to secure the same payload?

Probably instead just ride the bitcoin wave hard as hell and start my own game dev company.

Also I'd be better equipped towards mad anxiety disorder. That shit absolutely ruined my life and it took about 3 years before I realised something was actually wrong.

Convince my parents to put all their money in some fruit company about apples.

Gosh, I don't even know. To be back in that traumatizing household?

I wouldn't make it very long, I don't think.

Maybe I'd steal some money and run away to a different country before 9/11 makes everything harder.

I'd predict 9/11 five years early. Nobody would believe me. How would a kid this young even know these words I'm saying? What can an 8 year old possibly know about Al Queda and the Taliban? How did he even hear about these organizations in the first place, they'd ask. His parents must leave the TV tuned to the news all day, they'd say. What an active imagination this young man has.

I think I'd end up creating my own 11.22.63 scenario.