I am always amazed how in such a reduced style designers can express a unique personality through these nine little bricks. You have found elegant solutions for almost all letters, making it srangely readable. The only character in my opinion that remains ambiguous is the G, too close to a B, in my opinion, but I know it is very difficult to avoid ambiguity with this grid.
I love particularly your art deco E.

i ADD an image showing differnt solutions I found for the G in collection of 3x3 fonts. The last one is from an incredible one named "font3x3"(sorry, I don't remember where I found it) wich is the only attempt to make a real lowercase accompanying the uppercase, in fact it is the "g"

• No lowercase : what a pity !
• No punctuation : same 'shame' !
• Duplicates(!) : 2 === Z ; 5 === S.
• Uniform 3x3 size : nice !
• Possible improvements : new G (Neurone's 1st glyph) ; new or/and exchanged O/Q/0 (font weights can help, and Q has more glyphs) ; new E (derived F) ; a few more pixels to fix the weight (J, N, V/Y)…
• @ Neurone : well done, you're on the way to design your own complete 3x3 font with unique lowercase letters - it's like like the g(raal) that a few specialists already found in the past… ;-)