OP: https://vexforum.com/index.php/30026-sg9-clarification
The short answer is no, it is not legal.
The game manual states
The 2 cones not on a mobile goal would be counted as unstacked, per the definition of stacked:
So since the bottom cone is not on a goal or a stacked cone, it is not stacked. Same for the top one. Therefore the robot is in possesion of more than one unstacked cone, which is illegal, and can result in DQ if deemed match affecting.
wait but what about three cones
it’s ok ill hold the third one by the top
Try doing it in a match 
I don’t know what the question was (it apparently was deleted by the time of this writing), but it seems like it was about touching a stacked cone in the middle. In that case, I disagree with your answer on the basis of <SG9> Note 2, which states in part:
This note in this very specific case overrules the first part of the definition of Stacked, thus it would be legal to contact a cone in the middle.
The question was regarding holding two cones that are “stacked” but not on a mobile goal
Oh well in that case that’s illegal. I retract my reply.
I almost had a heart-attack since our robot stacks cones upon another cone, then places that stack on a mobile base. The intention of the rule is stated in the game manual: to guard against cone hoarding, shoving them all to one side to keep your opponent from being able to get them.
No, this is still illegal. The rule does talk about hoarding in note 1, but note 2 extends the purpose of the rule to cone stacking as well. Not to mention a previous Q&A has already ruled this as in violation of SG9. Here is the appropriate Q&A: Answered: SG9 - VRC > In The Zone (17/18) - VEX Forum
I see.