I'd start with the level 20. You won't need to spend the dust and candies on it to get it to a point where it's usable like you would need to for the 6.5 or the 9 (unless you're looking to use in pvp Great league, maybe?). The level 35 could be evolved and utilized if you don't have other high level rock attackers.
I have 4 cranidos
Lvl. HP atk def. Iv%
6.5 13/15/15 lucky 96
9 11/15/13 lub 13/15/12 lucky 87-89
20 11/15/15 91
35 13-14/0-5/4-7 47-49
I am wondering which should i first evolve 6.5 or 35 and i am thinking that 9 is not worth anything i am right?
Thanks everyone i decided on 96% and waiting for candy
I have tyranitars golems and rhydons as rock atackers but even if only to 30 lvl difrence im candy is 45 while in dust i am saving 14 k dust on 6.5 becouse of lucky i think that under 30 lvl is useless for me becouse i have golem 39 lvl i am asking abaut 35 becouse i am afraid of posibility 0 atk
I wouldnt say that the level 9 isn't worth anything even though it's IVs are rather low. I will always choose to power up/max a lucky over a non lucky even if its IVs are worst simply because the stardust savings are just so significant. (And IVs aren't really that important)
If you're low on stardust, always choose the lucky.