I don't discount people that got it in secondary markets. It's not like they're only buying a few shares. I can't find outside sources. The most legit one is from WSJ[0], 200k investment in 2009. Hopefully they verified holdings and date of investment before printing.
Crunchbase does list him as Angel/Seed Round investor in Uber in 2010[1].
[0] https://outline.com/8HHZFF
[1]https://www.crunchbase.com/funding_round/uber-angel--c76f942...