Đầu Phun Alien Ultralight X1

The lightest toolhead I could think of for an MGN9C based gantry, without getting super weird.

The Bambu X1C hotend is light and capable (and clones of it are available cheaply!). Add a 3010 fan for hotend cooling, and an ECAS04 collet to attach the bowden tube securely. Integrate mounting points for MGN9C carriage and belts. Add a draft shield so the rear curtain fan isn't blowing directly on the hotend.

Print bowden-side down and use tree supports. You should have to push the ECAS04 collet extremely hard to get it seated in the adapter. Add a small (~2mm) length of PTFE tube in the 4mm space between the collet and the hotend.

Cut short lengths of 1.6mm steel and thread them through the sides of this part, to act as belt anchors.

Attach this to the MGN9C carriage before intalling the hotend, as that will cover the screws when it is installed. 

Install the hotend, then finally, attach a fan, and connect the belts. You may need to drill the fan mounting holes out (if your fan takes M3 hardware). If so, you can probably just screw those directly into the plastic (not need nuts).

All hardware apart from the 1.6mm steel rods (so, the nuts and bolts) should be aluminium to save weight.