Evolve a Dratini with CP 389 and IV 96%?

the question answer itself, were you will find another good dranity like this ? and we have a x2 stardust event

That will be a 1500 cp ish dragonite, that's gonna take a solid amount of dratini candy and dust to get into fighting shape, for defending at least. It may be close to perfect, but when that's all said it done, it's only going to net you ~50 more cp than an easier to power up one. The last two Dratini I've hatched were 478 CP, 89% IV and 499 CP, 82% IV so I think you can find a happier medium between good IVs and something you don't have to spend a massive amount of dust on (which is the biggest limiting resource in the game.)

If you've got enough candies to power it up too, then yes. See if it's got a good moveset first though.

It'll cost you 203 candies in total to evolve it as well as to power it up from level 16 to 29.5 (your current maximum), but you don't need to power it up all the way for it to be usable. Even at level 20 it'll be usable, and that's "only" 16 candies to power it up from level 16.

If the moveset you get is undesired, keep it in case we're given the ability to change movesets in the future.

I would, depending on the moveset it gets. It's only 4 levels below a hatch. It's not the smartest thing to do but it sure does feel good to have some good mons on your team, especially if you did a lot of grinding for them.

If you got the dust and candies and have access to dratini spawns, then absolutely evolve. Just pray it gets DB/DC or SW/DP.

You may like to power up it all the way until your level.

The truth is if your Dragonite knows Dragon Breath you won't have to power him up too much anyway.

I took a risk and evolved a Level 11 Dratini 86%, 15 Attack stat and got Steel Wing. That sucks, that I had to power up because he's only there for defense (and it was before the Gym-Update).

Nevertheless, I would do it and if it's got Dragon Breath you'll be fine with a lower CP Dragonite.