I'm a little new to the VM world so I'm wondering if Rob Thomas has ever said what happened immediately following season 3? Like how did Logan and Veronica just not talk for 9 years? They didn't see each other after what happened in the series finale or what? I've seen the movie but I'm still confused!
Welcome to the fandom, anon!
Yep, L/V went nine long years without speaking to each other.
The way I understand it, Veronica left for her summer internship at Quantico right after the finale, and never came back. She transferred to Stanford after the summer and then Columbia Law.
I don’t think Rob Thomas every spelled it out step-by-step, but if you’d like to read speculation, I highly recommend @bryrosea‘s 9-Years fics: Waste of Breath and A Quartz Contentment. They may not be official canon, but they should be.