Yes and I think so.
Although I don't think just 1 person can make much of a difference unless that player is both high ranking (Rank 5) and has a very large cargo ship.
Most sabotaging will be from truckers hauling materials to systems that are losers for the faction, pushing them from Prep systems to Expansion systems, then ensuring that they are Expanded into.
Locate a Prep system that has a super low income (5 cc per cycle) or a negative income (-4 CC per cycle). Then truck as many materials as you can to the system during prep. (This is why Rank 5 and a large cargo ship is needed. You may need to hit a 3000+ point Prep value or more to push it to the top of the list).
If the system is both a very low cost, and a negative income generator, you can usually sneak the system onto the Expansion List if the Power has enough extra CC to spend that it will pick up the system.
If the system makes the Expansion list, then you would need to do the particular requirements to have a successful Expansion of the system. If the Power has trucking for both Prep and Expansion, you would need to truck during both steps. If the Power has Combat Expansions, you would need to switch to a combat ship (or loadout) and work the specific battle zones in the Expansion system for that power.
If you work on Fortification, only contribute to the ones that are losses for the system, especially if they are being undermined.
Stay away from the high income systems during Fortification, especially if they are being undermined.