Which coast is the boat on?
A 9m powerboat can be trailered. You might be able to simply trailer the boat home, but I don't know what the political climate, or other socio-political concerns there may be between trailering through Costa Rica, Nicaragua, Honduras, Guatemala, and Mexico, to get to the U.S., but trying to bring a boat into the US can be tricky.
Maybe trailering to a jump-off point and delivering the boat from there to avoid dangerous regions and coastlines.
Tell us a little more about the vessel. What's her range and speed?
I'd first look at a container ship, less confrontation with someone who may want to confiscate your Costa Rican purchase.
If she can make the trip on her own, that might be a reasonable option. Make sure to talk to the authorities ahead of time, tell them what you're trying to do, and get their advice.
-Will