diff --git a/.gitmodules b/.gitmodules
index 6edb2eea5b2..498bf7eb102 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,4 +1,4 @@
 [submodule "vendor/llhttp"]
     path = vendor/llhttp
     url = https://github.com/nodejs/llhttp.git
-    branch = v8.x
+    branch = main
diff --git a/CHANGES/7484.misc b/CHANGES/7484.misc
new file mode 100644
index 00000000000..ff540ceb709
--- /dev/null
+++ b/CHANGES/7484.misc
@@ -0,0 +1 @@
+Upgraded llhttp parser to v9 -- by :user:`Dreamsorcerer`
diff --git a/aiohttp/_cparser.pxd b/aiohttp/_cparser.pxd
index 165dd61d8a9..9dfb04134d1 100644
--- a/aiohttp/_cparser.pxd
+++ b/aiohttp/_cparser.pxd
@@ -1,13 +1,4 @@
-from libc.stdint cimport (
-    int8_t,
-    int16_t,
-    int32_t,
-    int64_t,
-    uint8_t,
-    uint16_t,
-    uint32_t,
-    uint64_t,
-)
+from libc.stdint cimport int32_t, uint8_t, uint16_t, uint64_t
 
 
 cdef extern from "../vendor/llhttp/build/llhttp.h":
@@ -88,30 +79,14 @@ cdef extern from "../vendor/llhttp/build/llhttp.h":
     ctypedef llhttp_errno llhttp_errno_t
 
     enum llhttp_flags:
-        F_CONNECTION_KEEP_ALIVE,
-        F_CONNECTION_CLOSE,
-        F_CONNECTION_UPGRADE,
         F_CHUNKED,
-        F_UPGRADE,
-        F_CONTENT_LENGTH,
-        F_SKIPBODY,
-        F_TRAILING,
-        F_TRANSFER_ENCODING
-
-    enum llhttp_lenient_flags:
-        LENIENT_HEADERS,
-        LENIENT_CHUNKED_LENGTH
+        F_CONTENT_LENGTH
 
     enum llhttp_type:
         HTTP_REQUEST,
         HTTP_RESPONSE,
         HTTP_BOTH
 
-    enum llhttp_finish_t:
-        HTTP_FINISH_SAFE,
-        HTTP_FINISH_SAFE_WITH_CB,
-        HTTP_FINISH_UNSAFE
-
     enum llhttp_method:
         HTTP_DELETE,
         HTTP_GET,
@@ -167,24 +142,15 @@ cdef extern from "../vendor/llhttp/build/llhttp.h":
                  const llhttp_settings_t* settings)
 
     llhttp_errno_t llhttp_execute(llhttp_t* parser, const char* data, size_t len)
-    llhttp_errno_t llhttp_finish(llhttp_t* parser)
-
-    int llhttp_message_needs_eof(const llhttp_t* parser)
 
     int llhttp_should_keep_alive(const llhttp_t* parser)
 
-    void llhttp_pause(llhttp_t* parser)
-    void llhttp_resume(llhttp_t* parser)
-
     void llhttp_resume_after_upgrade(llhttp_t* parser)
 
     llhttp_errno_t llhttp_get_errno(const llhttp_t* parser)
     const char* llhttp_get_error_reason(const llhttp_t* parser)
-    void llhttp_set_error_reason(llhttp_t* parser, const char* reason)
     const char* llhttp_get_error_pos(const llhttp_t* parser)
-    const char* llhttp_errno_name(llhttp_errno_t err)
 
     const char* llhttp_method_name(llhttp_method_t method)
 
     void llhttp_set_lenient_headers(llhttp_t* parser, int enabled)
-    void llhttp_set_lenient_chunked_length(llhttp_t* parser, int enabled)
diff --git a/tests/test_http_parser.py b/tests/test_http_parser.py
index 344d0776633..e8d38c193bd 100644
--- a/tests/test_http_parser.py
+++ b/tests/test_http_parser.py
@@ -861,19 +861,6 @@ def test_partial_url(parser) -> None:
     assert payload.is_eof()
 
 
-def test_url_parse_non_strict_mode(parser) -> None:
-    payload = "GET /test/тест HTTP/1.1\r\n\r\n".encode()
-    messages, upgrade, tail = parser.feed_data(payload)
-    assert len(messages) == 1
-
-    msg, payload = messages[0]
-
-    assert msg.method == "GET"
-    assert msg.path == "/test/тест"
-    assert msg.version == (1, 1)
-    assert payload.is_eof()
-
-
 @pytest.mark.parametrize(
     ("uri", "path", "query", "fragment"),
     [
@@ -898,6 +885,8 @@ def test_parse_uri_percent_encoded(parser, uri, path, query, fragment) -> None:
 
 
 def test_parse_uri_utf8(parser) -> None:
+    if not isinstance(parser, HttpRequestParserPy):
+        pytest.xfail("Not valid HTTP. Maybe update py-parser to reject later.")
     text = ("GET /путь?ключ=знач#фраг HTTP/1.1\r\n\r\n").encode()
     messages, upgrade, tail = parser.feed_data(text)
     msg = messages[0][0]
diff --git a/vendor/README.rst b/vendor/README.rst
index 1f10e20cce2..6156f37f80e 100644
--- a/vendor/README.rst
+++ b/vendor/README.rst
@@ -5,7 +5,7 @@ When building aiohttp from source, there is a pure Python parser used by default
 For better performance, you may want to build the higher performance C parser.
 
 To build this ``llhttp`` parser, first get/update the submodules (to update to a
-newer release, add ``--remote`` and check the branch in ``.gitmodules``)::
+newer release, add ``--remote``)::
 
     git submodule update --init --recursive
 
diff --git a/vendor/llhttp b/vendor/llhttp
index 7e18596bae8..ea67741b1b7 160000
--- a/vendor/llhttp
+++ b/vendor/llhttp
@@ -1 +1 @@
-Subproject commit 7e18596bae8f63692ded9d3250d5d984fe90dcfb
+Subproject commit ea67741b1b70c52d43d8520bf1750e4a7427e827