Other than Save Sara Connor, everyone has this wrong.
Faking an identity is easy. Back then it was all paper, and for Americans, SSNs were only just barely standard. Say you grew up in some rural bumblefuck place and sign up for everything fresh. Full Tara Westover story would work.
Next, find your grandparents. Convince them you know them from something through a friend they've mentioned to you and crash on their couch long enough to get a basic job, then apartment, car, and grow a moustache. Which should take about 3-4 weeks. Restist your mom's advances and attempts to take you to a high school dance.
Next, get to the west coast and start selling and buying up real estate. Buy and sell Hollywood back to itself until 1988. Then start buying real estate in New York. On the side, buy stock in all the classic tech companies, Nintendo, and in the military industrial complex. By 1993, you'd be a millionaire. From there, do whatever you want. Buy early and sell AOL stock. Blackberry. GE.
Then do good things in the world. Pull the fire alarms in the WTC at 8:45am on 9/11. Get a certain orange therapy so he stays with Ivanna for the kids. Invent Paypal first and steal the other half of it from Peter Thiel. Convince Woz, Gates, and Jobs that the future is in open source software. Find Linus Torvalds and mail him a billion euros. The morning before the Citizens United decision, bribe Clarence Thomas to abstain and pull the fire alarm. Mail Bernie Sanders $52 every week, anonymously. Get the pilots of Pam Am 103 super hammered the night before so the fight gets cancelled. Organize a London public transit boycott for 7/6/2005 lasting 3 days. Find the people that cancelled Firefly and murder them, wear their faces as a mask, and make sure the series goes at least 5 seasons.
You know, chill stuff like that.