Note that to avoid deepstrike threat, what counts is the number of hops from a planet that's not owned by the AI. It doesn't matter whether such planet is owned by you or no-one. So if you can send a few Raid Starships or teleporters through and pop the command station in your target planet, that will immediately end deepstrike threat generation. You can actually colonise the planet at your leisure.
Also, if two non-AI planets are 9 or fewer hops apart , you won't generate deepstrike threat while moving between them, because all the 8 or fewer intermediate planets are <5 hops from a non-AI planet.