diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 74118fe8..75680e55 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -26,18 +26,15 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.11", "3.12", "3.13", "3.14"]
-        sphinx: [">=8,<9"]
+        sphinx: [">=8,<9", ">=9,<10"]
         os: [ubuntu-latest]
         include:
-        # - os: ubuntu-latest
-        #   python-version: "3.11"
-        #   sphinx: ">=7,<8"
         - os: windows-latest
           python-version: "3.11"
           sphinx: ">=8,<9"
         - os: windows-latest
           python-version: "3.14"
-          sphinx: ">=8,<9"
+          sphinx: ">=9,<10"
 
     runs-on: ${{ matrix.os }}
 
diff --git a/pyproject.toml b/pyproject.toml
index c2ffb213..c83610ad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ dependencies = [
     "markdown-it-py~=4.0",
     "mdit-py-plugins~=0.5",
     "pyyaml",
-    "sphinx>=8,<9",
+    "sphinx>=8,<10",
 ]
 
 [project.urls]
diff --git a/tests/test_renderers/fixtures/sphinx_directives.md b/tests/test_renderers/fixtures/sphinx_directives.md
index 357ba114..99370f05 100644
--- a/tests/test_renderers/fixtures/sphinx_directives.md
+++ b/tests/test_renderers/fixtures/sphinx_directives.md
@@ -386,7 +386,7 @@ term 2 : B
                         Definition of both terms.
 .
 
-SPHINX4-SKIP productionlist (`sphinx.domains.std.ProductionList`):
+SKIP productionlist (`sphinx.domains.std.ProductionList`):
 .
 ```{productionlist} try_stmt: try1_stmt | try2_stmt
 ```
@@ -426,7 +426,7 @@ rst:directive (`sphinx.domains.rst.ReSTDirective`):
         <desc_content>
 .
 
-SPHINX4-SKIP rst:directive:option (`sphinx.domains.rst.ReSTDirectiveOption`):
+SKIP rst:directive:option (`sphinx.domains.rst.ReSTDirectiveOption`):
 .
 ```{rst:directive:option} a
 ```
diff --git a/tests/test_renderers/fixtures/sphinx_syntax_elements.md b/tests/test_renderers/fixtures/sphinx_syntax_elements.md
index 1f6e1fcb..37a518ff 100644
--- a/tests/test_renderers/fixtures/sphinx_syntax_elements.md
+++ b/tests/test_renderers/fixtures/sphinx_syntax_elements.md
@@ -169,7 +169,7 @@ Image empty:
 .
 <document source="<src>/index.md">
     <paragraph>
-        <image alt="" uri="">
+        <image alt="" candidates="{'*': '.'}" original_uri="" uri=".">
 .
 
 Image with alt and title:
@@ -178,7 +178,7 @@ Image with alt and title:
 .
 <document source="<src>/index.md">
     <paragraph>
-        <image alt="alt" title="title" uri="src">
+        <image alt="alt" candidates="{'*': 'src'}" title="title" uri="src">
 .
 
 Image with escapable html:
@@ -187,7 +187,7 @@ Image with escapable html:
 .
 <document source="<src>/index.md">
     <paragraph>
-        <image alt="alt" uri="http://www.google%3C%3E.com">
+        <image alt="alt" candidates="{'?': 'http://www.google%3C%3E.com'}" uri="http://www.google%3C%3E.com">
 .
 
 Block Quote:
diff --git a/tests/test_renderers/test_fixtures_sphinx.py b/tests/test_renderers/test_fixtures_sphinx.py
index 32e3c189..3b5a4ca4 100644
--- a/tests/test_renderers/test_fixtures_sphinx.py
+++ b/tests/test_renderers/test_fixtures_sphinx.py
@@ -34,10 +34,16 @@ def _apply_transforms(self):
 
     result = sphinx_doctree(file_params.content, "index.md")
     pformat = result.pformat("index")
-    # changed in docutils 0.20.1
-    pformat = pformat.replace(
-        '<literal classes="code" language="">', '<literal classes="code">'
-    )
+    replacements = {
+        # changed in docutils 0.20.1
+        '<literal classes="code" language="">': '<literal classes="code">',
+        # changed in sphinx 9
+        '<image alt="" uri="">': '<image alt="" candidates="{\'*\': \'.\'}" original_uri="" uri=".">',
+        '<image alt="alt" title="title" uri="src">': '<image alt="alt" candidates="{\'*\': \'src\'}" title="title" uri="src">',
+        '<image alt="alt" uri="http://www.google%3C%3E.com">': '<image alt="alt" candidates="{\'?\': \'http://www.google%3C%3E.com\'}" uri="http://www.google%3C%3E.com">',
+    }
+    for old, new in replacements.items():
+        pformat = pformat.replace(old, new)
     file_params.assert_expected(pformat, rstrip_lines=True)
 
 
@@ -89,9 +95,7 @@ def test_sphinx_directives(
 ):
     # TODO fix skipped directives
     # TODO test domain directives
-    if file_params.title.startswith("SKIP") or file_params.title.startswith(
-        "SPHINX4-SKIP"
-    ):
+    if file_params.title.startswith("SKIP"):
         pytest.skip(file_params.title)
 
     sphinx_doctree_no_tr.set_conf({"extensions": ["myst_parser"]})
diff --git a/tox.ini b/tox.ini
index cd87af04..1a18f9f8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,12 +11,12 @@
 # then then deleting compiled files has been found to fix it: `find . -name \*.pyc -delete`
 
 [tox]
-envlist = py311-sphinx8
+envlist = py311-sphinx9
 
 [testenv]
 usedevelop = true
 
-[testenv:py{311,312,313,314}-sphinx{8}]
+[testenv:py{311,312,313,314}-sphinx{8,9}]
 deps =
     sphinx8: sphinx>=8,<9
 extras =