Hey!
Honestly the big hurdle with AspectJ 1.9.0 was just to support the module system, i.e. how they had repackaged the JDK. There are many things we could do, but haven't found the bandwidth yet. The faster release cadence for the JDK means we seem to be spending more time just keeping up (see the 1.9.2 that just came out to support Java11).
If you look in the 1.9.0 readme I put a small example of working with AspectJ and the module system:
https://www.eclipse.org/aspectj/doc/released/README-190.html - both a source and binary weaving example. We do ship the AspectJ elements (weaver/runtime/compiler) as automatic modules so they will play nicely in that world. Perhaps the key drawback at the moment is that if you do use aspects to connect some modules together that may require updates to the module-info file and currently AspectJ does not 'weave' that to update it - you have to do it manually. We also don't have inpath equivalents of module-path (i.e. an inpath where module constraints are enforced). Wish I had more for you but that's as far as I've gotten lately.
cheers,
Andy