I use the Mojo too as my source and I have bought the IER-M9, but still waiting to get them which could take up to 2 more months since they are with a friend in Australia...
I heard the M9 once a year ago and they are good without a doubt, what makes them special is that they have been called "The most DD like BA IEM". This really attracts me, as I find BA's a little too fast to be natural, and like DD timbre better.
But it all comes down to what you are looking for.
Crinacle's list is a good starting point, then if you can name your priorities different picks will come out on top.
M9 - warmish allrounder
CA Andromeda - neutral soundstage monster with very good midrange and added upper treble sparkle
Sony EX1000 - veteran with amazing clarity and soundstage, a bit intense, amazing bass extension and texture
Sony IER-Z1R - American V8 muscle car sound, but also refined (M9 on steroids)
Moondrop S8 - Technical & musical
https://crinacle.com/2020/01/08/cliffnotes-moondrop-s8-a8-wake-up-call/
Fearless S8F - V-shaped, bass-highs boosted detail, good value
Sony IER-M7 - M9 a little tamed, significantly cheaper
JVC FDX1 (or FD01 or FD02 if you mod them yourself) - Smooth allrounder and value king
To be honest - depending on your preferences I think each of them is a good option.
I'd consider getting a JVC FD02 from Amazon Japan for cheap (<€200 including importation) and use it as a beater IEM.
With a simple mod and cable upgrade they are very enjoyable and get a lot of listening time next to my more expensive IEMs.
Cheers!