From 31 Dec. 1969 - 17 Jan. 1970 (The Mother's Agenda, Vols. 10-11) the Mother described her vision for a Temple (the Matrimandir) in Auroville. Chronicles of the Inner Chamber (by Patrizia Norelli-Bachelet) describes Auroville's destortion of the Mother's original Vision. Available Free Online and in Book format.
This is a blog post of mine, which includes excerpts from the Mother's Agenda discussing the number 9 as "the figure of birth" and 72 as a symbol of "the work of gestation for the [new] birth of the divine consciousness". 1872, Sri Aurobindo's birth year contains the number 72 and reduces to 9 (via Theosophical Addition)