SG9 rule clarification

Is it legal for a robot to possess both a stack (mobile base with cones stacked on it) along with another cone.

It says in Note 2 that stacks do not count towards the possession limit.

The reason for asking is because our team was wondering about the legality of placing cones on top of mobile goals that are being carried by the robot.

Yes. You can carry a mobile goal with stacked cones and another unstacked cone. The mobile goal and the cones stacked on top do not count as your 1 allowed cone.