Update scikit-learn requirement from >=1.4 to >=1.9.0

[dependabot]

Updates the requirements on scikit-learn to permit the latest version.

Release notes

Sourced from scikit-learn's releases.

Scikit-learn 1.9.0

We're happy to announce the 1.9.0 release.

You can read the release highlights under https://scikit-learn.org/stable/auto_examples/release_highlights/plot_release_highlights_1_9_0.html and the long version of the change log under https://scikit-learn.org/stable/whats_new/v1.9.html

This release adds narwhals as a new dependency that will help to improve dataframe interoperability across the project.

This version supports Python versions 3.11 to 3.14.

You can upgrade with pip as usual:

pip install -U scikit-learn

The conda-forge builds can be installed using:

conda install -c conda-forge scikit-learn

Commits

• 77def0e trigger wheel builder [cd build]
• ee7c0b0 generate changelog
• 3d7fb04 bump version
• 8954e7b DOC Release highlights for 1.9 (#34147)
• 73a3eab Fix: Array-API - avoid failing for numpy fit + predict with sparse or array-l...
• 8839aae DOC Thread-safety requirement for open_listener message consumer callback (#3...
• 4d2476a DOC Refactor array API docs page (#34054)
• f9f812f 🔒 🤖 CI Update lock files for scipy-dev CI build(s) 🔒 🤖 ...
• d779dc3 🔒 🤖 CI Update lock files for free-threaded CI build(s) 🔒 :rob...
• 6a03cf0 🔒 🤖 CI Update lock files for array-api CI build(s) 🔒 🤖 ...
• Additional commits viewable in compare view

[sefaav]

@dependabot rebase

[dependabot]

OK, I won't notify you again about this release, but will get in touch when a new version is available. If you'd rather skip all updates until the next major or minor version, let me know by commenting @dependabot ignore this major version or @dependabot ignore this minor version. You can also ignore all major, minor, or patch releases for a dependency by adding an ignore condition with the desired update_types to your config file.

If you change your mind, just re-open this PR and I'll resolve any conflicts on it.