The crowned “9” was the charge mark of the Rennes mint, but this piece was made in Saint-Malo, which was under the Rennes jursidiction during the ancien régime. Top to bottom:
1) A club + 84: Saint-Malo countermark for 1784, but in actuality probably used ca. May 1785 to ca. 1787.
2) "aa" + a crowned lozenge & two pellets: maker’s mark of André Audouard (1711-1793; master 1743).
3) Crowned “9”: Charge mark of the Rennes mint, 1781-1789.
Interesting side note: Audouard spent some of his journeyman years, ca. 1735-42 in North America.
Hope this helps!
Ref: Jean-Jacques Rioult,Sophie Vergne, et al. Orfèvres de Haute Bretagne (Rennes: Presses Universitaires de Rennes, 2006), pp. 149 & 161.