Suffice it to say, it works.
 
The 9th house cusp, is the conception.  The planets in and around it, show the enviorment of the mother and even the people she was involved with, and how she reacted in life.
In your one daughter's case, (not all of your children), the way you were being back then;, when she was conceived, (i.e. when her soul took upon herself, this lifetime), the vibrations you were emitting then, were "right" for this soul to enter into.
 
So, seeing the 9th house cusp Ruler, i.e. Capricorn in this case, you get the picture , as well as Mars being the closest to the 9th, (and the sign representing Mars in this chart). You should go back in your mind's eye', and try to remember, "how" the circumstances were with each of your children, IF you wish to  understand them more fully. They are NOT of course YOU , but came through you both physically as well a vibrationally (spiritually).
 
Mann, goes around the zodiac this way, unraveling an entire likelihood, of probable events, from conception, to gestation, to birth (the ASC), and after birth, from the 1st house to the death, all events may be conceptualized, as probable paths, and outcomes.......but of course, always recognizing that in the end, of the travel, and even during the path of psychological timing, one may choose many various paths to develop themselves by.
No one answer then may be seen as to prognosticate exactly , as no one knows what one soul may choose in life to act out or play out.
 
BUT, what can be seen, just like death itself, is the "after they choose", and you can see when something big will occur, (just not WHAT  the something is)...using this method of delineation.
 
So, just like many other tools in astrology, this certainly is a great one to utilize to help others.,IMO.
 
As for the Moon representing mother, of course that too is true, as it's the "archetype", in our deeper psyche that points to this particular Light, as such, in the same way that Sun is the other archeytpe symbol, pointing to father and the respresentation of what a father image might be, (not literally of course), but symbolically speaking.
For instance, say you were a "Test Tube" baby, well - you would still  have the Sun in your natal wouldn't you? But the Sun sign itself, just as the Moon symbol as such, will only reveal the associative qualities or traits of the parental biology.
 
In astrology, one should try to think "outside the box" IMO, - but most do not, until they force themselves to do so.
This is why Tad Mann was so successful, IMO, - because he not only thought "outside the box", but created what he termed, "A New Vision of Astrology"
But again, I think the title is a good one, but the understanding of it being, it's a New Vision, but based upon ancient precepts is more to the point.
 
 
(you can see it here)below, an article about this theory that was written up in Mountain Magazine
 
http://en.wikipedia.org/wiki/A._T._Mann
 
http://www.atmann.net/tma.htm
 
some background of mixing psychology, astrology and the higher learnings, or leanings like Zen:
http://www.whirledwydeweb.com/astrologyinbali/tadmann.html