I'm 9w8 and I don't think I'm as super trusting of people and ideas as some descriptions of 9 seem to portray. Could it be that the wing 8 adds the need to have things under control, and thus be more cautious of things in general?
In the practice of tolerance, one's enemy is the best teacher.
I think the wing 8 make 9s quicker to realise when people are abusing of them, or are untrustworthy. However, they still candid, trusting and merging when they meet people at first.
EsTP 6w7 Sx/Sp
E=60% S=55% T=70% P=80%
"I don't believe in guilt, I only believe in living on impulses"
"Stereotypes about personality and gender turn out to be fairly accurate: ... On the binary Myers-Briggs measure, the thinking-feeling breakdown is about 30/70 for women versus 60/40 for men." ~ Bryan Caplan
No. Just when you lose the trust and cross the line, the transgression will be recorded and reparations will be required. Though as soon as the situation is over I'm usually back to 9 and so would trust an axe murderer again....apparently. Only to other's do I seem too trusting, to me it's a calculation of risk and an assessment of character. Simple probability.