9.9 is working against software freedom
'''9.9 License Must Not Contaminate Other Software'''
The license must not place restrictions on other software that is distributed along with the licensed software. For example, the license must not insist that all other programs distributed on the same medium must be free software.
This formulation says without naming it that the GPL is "contaminating" other software with "restrictions". This is not only short-sighted, it demonstrates a complete misunderstanding of what free software is about. Free software is about user control over their computing. Restricting user control goes against the spirit of software freedom.
Allowing proprietary software to build upon free software is a problem. Allowing free software to build upon non-free software (e.g., proprietary firmware) is also a problem, but of a different nature: it enables a user to exert control over his machine containing non-free parts (mostly, hardware parts). If this point is to solve that problem, then it should not attack the GPL.
Introducing such a "feature" in the Devuan constitution would make it a distro that will be more restrictive than Debian is, and will jeopardize all common work with the Free Software Foundation and the GNU project. It is antagonist with the objective to maintain GNU utilities at the core of the system, and in my opinion much worse than having systemd taking over.
I would not like to participate in an anti-GPL open-source project that takes the cover of a free software project defending "freedom of choice" rather than "software freedom", and from what I read, this point is exactly that.