Cooking Scrambled Eggs ends up with excess liquid
You've already spotted two of the possible reasons for scrambled eggs to sit in a pool of water: condensation, and the other ingredients in the scramble seeping moisture.  The condensation you can deal with by leaving the eggs to sit (off heat) for 2-3 minutes before plating them.  You're already taking a stab at making the fillings not wet; aside from cooking them well (and making sure to cook off any moisture), some wet fillings (zucchini, tomatoes, etc.) can also benefit from salting and blotting with paper towels.

However, there's another place for moisture to come from, and that's the eggs themselves.  This problem is called "weeping", and affects cooked eggs in all forms (scrambled eggs, quiche, meringues, even boiled eggs).  Over time, as cooked eggs sit, their protein structure squeezes out the water in them.  Various problems can cause that to happen within minutes, as it is in your case.

Here's some tips for avoiding weepy scrambled eggs:


Add very little, or no, extra liquid to the eggs.  This means that if you tend to add milk or cream to your beaten eggs, it should be no more than 2 tsp.
Make sure to scramble the eggs uncovered, so their moisture can escape as steam.
Salt the beaten eggs 15-30 minutes before cooking them, instead of salting them while cooking.  This changes the protein structure of the egg white so that it's less likely to lose moisture.  If you forget, or don't have time, then wait and salt the eggs on the plate; salting them in the pan is almost a guarantee of weeping, in my experience (and Kenji's).
Avoid overcooking the eggs.  If you cook them "dry", they're more likely to weep. If you like your scrambled eggs dry, then cook them until almost firm, and let them continue setting up off-heat.  Try cooking over low-medium heat until you get the hang of things.
In addition to wet fillings, fillings that are very acidic (like fresh tomatoes or tomatillos) can affect the eggs and cause them to weep, so consider adding these as a topping instead of cooked into the eggs.


Some additional references:


Why do Scrambled Eggs get Watery
Serious Eats tips on Scrambled Eggs