Using the current Rawhide package:

> $ fedpkg --release epel9 mockbuild
> […]
> No matching package to install: 'python3dist(cython) >= 0.29.24'
> No matching package to install: 'python3dist(matplotlib)'

From CHANGES.txt:

> - Require Cython >= 0.29.24 to support Python 3.10 (#1224).

So the minimum Cython version can be loosened or patched out for EPEL9.

Meanwhile, matplotlib (bug 2041315) appears to be used only for documentation and examples, so we can get by without that.

So I think this will be possible with some minor adaptation.

https://pagure.io/releng/fedora-scm-requests/issue/45211

FEDORA-EPEL-2022-0956225895 has been submitted as an update to Fedora EPEL 9. https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2022-0956225895

FEDORA-EPEL-2022-0956225895 has been pushed to the Fedora EPEL 9 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2022-0956225895

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

FEDORA-EPEL-2022-0956225895 has been pushed to the Fedora EPEL 9 stable repository.
If problem still persists, please make note of it in this bug report.