Yes it's core is composed of incredibly dense gasses so it would be impossible to go to the planet directly, however the four Galilean moons (Io, Ganymede, Europa, and Callisto) are solid masses that are quite large and by all means likely to be terraformed in the Destiny universe. If you have a decent telescope you can actually make out a few of the moons depending on the cycle when looking at Jupiter. There is also rumors of a space type station within the upper layers of Jupiter's atmosphere (think cloud city) where the nine live that guardians may some day visit.

Right...moons...forgot about those. I thought the Cabal blew them up.

I know that ghost mentions that the cabal will blow up planets and moons just for getting in their way, and they did blow up most of Mars' second moon Deimos, but I don't think there's anything conclusive on the status of Jupiters moons. It should be noted that Jupiter has 67 moons so the cabal could have blown up a few. Just for knowledge on moons Mercury- 0 Venus-0 Earth-1 Mars-2 Jupiter-67 Saturn-62 Uranus-27 Neptune-14 As far as being included in Destiny, only the 4 Galilean moons of Jupiter and the 7 principle moons of Saturn are large enough to be of any significance outside of the ones we've been to.

You did your research.

Was an astronomy major for half of my college career, it's a fun topic to learn about