diff --git a/.github/workflows/python.yml b/.github/workflows/python.yml
index 7ee6898a5..77d4e406f 100644
--- a/.github/workflows/python.yml
+++ b/.github/workflows/python.yml
@@ -144,7 +144,7 @@ jobs:
       - name: Cache intersphinx inventories
         uses: actions/cache@v5
         with:
-          path: python/doc/_build/doctrees/
+          path: python/doc/_build/doctrees/__intersphinx_cache__/
           key: intersphinx-${{ hashFiles('python/doc/source/conf.py') }}
           restore-keys: intersphinx-
 
diff --git a/python/pyproject.toml b/python/pyproject.toml
index e3672ff31..f36004a7d 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -70,7 +70,7 @@ docs = [
   "plotly",
   "pydata-sphinx-theme>=0.16",
   "seaborn",
-  "sphinx>=6",
+  "sphinx>=9",
   "sphinx-autodoc-typehints",
   "sphinx-copybutton",
   "sphinx-design",