Congrats, you got it !
To be precise, it is the EB.9, by Ermanno Bazzocchi (of MB.326 fame). If built it would have been called Macchi EB.9 (like is was done for Castoldi Macchi C.202 for example). Bazzocchi entered Macchi in 1941 as principal associate designer, hired by the company to substitute Castoldi in a few years (this happened in mid-45). The EB.9 was intended as an assault transport, designed to what looks like some sort of informal specification circulated by early 1942 that produced the SM.96 I (you know only the SM.96 II, that was a totally different beast) and later the SM.96 III. The design evolved for circa two years and it's final configuration was of more conventional shape, targeted to post-war medium capacity air transport for passenger/cargo. In this later incarnation, the EB.9 was benchmarked by Bazzocchi against two competing design, the Ca.179 and... the SM.99. Problem is that, while we have info on the Ca.179, there is absolutely nothing on the SM.99. My guess is that is was a wartime early designation of what later became the SM.104 (or the SM.105 twin first version, not the later detachable-pod configuration that is much better known). There is a no-designation SM October 1943 design for a tricycle-wheeled passenger transport, but is was considerably larger (4 Alfa 135). The EB.9 in this later version was still powerd by two Alfa 135s.
I'll post all the drawings of the EB.9 that are available, plus some specs. And then I'll reveal where you can find them and many more... for a modicum amount of money (no, it isn't ISP).