If you don't want to spend money on 9sec, but want the same protection without having to give up being able to hack someone, then this is the Strategy for you!
First off, find a method to disable your phones time out function. IF you are unfamiliar with Developer Mode, this can be done by downloading the "No Screen Off" app from Google Play. You can use other apps but this is the one I personally tested. Once you have the app up and running all you have to do now is keep your game actively playing.
While your account is active, you will be less likely to appear on the world map and people will not be able to retrace you. This essentially will make you a ghost.
Finally, the game does have a feature that allows other players to Hijack your network after constant activity over 3 hours. Don't worry though, the only thing that needs to happen is another player "Viewing" your network. If they don't attack and leave, all you have to do is log back in and the 3 hour time resets. I have only been using this stradegy for 2 days now, and the only time I have been hacked is during the night when I sleep as I am not dedicated, like others, to disturb my sleep for a game. So I could be wrong about the being "viewed" part is all it takes to reset the 3 hours. I'll keep y'all updated the first chance I get when I find out if this is wrong, or wait until someone who has been utilizing it longer reads this and corrects me.
**WARNING** there is a bug with the hijacking part that can cause you to be kicked in the middle of a hack and lose your programs, resources and rep. The developer is currently working on fixing this part though, so don't worry

For those that will call this cheating, the developers are aware of this stradegy as LurkingRage has informed them of this. The game's mechanics are considered "Balanced" at this time, so it is deemed a legit strategy.
So unless they implement something along the lines of:
1. A function that detects if there is input (complicated input, not just a basic tap as some apps can simulate this basic input) happening, and if not boots the account.
2. Make it to where the player has to answer a basic question after 2 hours of constant activity.
3. Give retrace the ability to hijack a network if the player isn't in the middle of a hack.
4. Or more extreme, temporarily banning someone for remaining constantly active for more than 14-16 hours a day.
You have nothing to worry about. Just keep your phone plugged in (or laptop for anyone running an android emulator), and call yourself a ""Good Player"" as you actively hide your network from other players, easily saving your resources while you climb past everyone on the leaderboard.
Combine this with minmaxing, or smurfing and you'll be exceptionally better than anyone utilizing only one of these.