The "holly" ideas have 2 origins: positive + negative.
It's possibly to use only one side, as the opposite should be single-valued linked with it.
> That only happens when types stray from their health.
"Healthy" - is the state where type has developed against own limits, where human overcame own type to higher level without types. All healthy states are similar. Types - is where the personal leveling starts and progresses. It should be related equally to positive and negative inner ideals-attachments.
If to take my 1 type - in the most healthy variant it reduces the tendency to fight with windmills, to do this more for the own pleasure than for good result. Developed 1 look as polite, stable and positive people, like good fathers to thoughts of which people want to follow themselves. They do not need to fight with people anymore. Developed 1 get the traits of its opposite 9 - its abbility to be liked, to live in harmony with the environment, instead of feeling anger and annoying fights with others. Same happens with 9 - it overcomes its passive and avoiding attitudes to active forming the reality closer to own ideals, while staying same cute and pleasant persons. Developed 1 and 9 become very similar, but they go to this from different sides.
Imagine a mountain. It has 1 peak. While types are the points at bottom of this mountain. There are many places-types at the bottom. The lower - the more distance may to be between places. Personal development is the way from the bottom to the peak which is the same for all, despite the place where you've started the way to the top.
Jung's typology and Enneagram types have similar conception of personal development. To develop means to overcome own type limits. You should stop to avoid own fears/weaks and stop to blindly idealize your pleasures/strongs specific for your type.
On Jung's T/F dichotomy.
T - is the reason. But there is no sense in the reason if people suffer when it is realized.
F - cares about emotional pleasure. But there is no sense in pleasure if it leads to objectively worse life (lesser possibility to stay alive).
The optimum point - is the balance of the opposite ideals/attachments.
That is why duality attracts us. Our nature wants to achive this optimum. In duals we see the supressed half of ourselves and also friends which may to help us overcome our non-integrity.