Relationship between type 4 and type 9

The artist and the peacemaker

Éponine (Les Misérables)
Frodo Baggins (LOTR)

Attraction

The 4 is attracted by the tolerance, patience, appeasement, idealism and listening of the 9.
The 9 is attracted by the compassion, passion, energy and emotional depth of the 4.
Both are sensitive, friendly, empathic, romantic and like to find that in each other.
The 4 feels completely accepted by the 9, so his fears of abandonment dissipate.
The 9 feels important with the attention of the 4, and likes to be stimulated by his energy and his passion.

Points where to be careful

4 pays exceptional attention to what he is missing, and with time, can become more demanding and critical towards 9. 9 gives unconditional acceptance to 4 and expects it in return. 4 wants excitement and intensity, while 9 wants comfort. This causes a conflicting problem. 4 can be dissatisfied with how relaxed the relationship is, and disappoint 9 who will close in on himself.
9 can perceive 4 as being too demanding, selfish, critical, dramatic and emotionally unstable.
4 can perceive 9 as being too disorganised, lazy, irresponsible, inefficient, boring and stubborn.