diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 7dcb14a819..5d8e1ebaa5 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -77,7 +77,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.10', '3.13']
+        python-version: ['3.9', '3.13']
     steps:
     - uses: actions/checkout@v4
       with:
@@ -121,12 +121,12 @@ jobs:
         # Jupyter notebooks are out-of-date
         # ( make -C tutorial/notebooks notebook )
     - name: Test with pytest
-      if: ${{ !(matrix.python-version == '3.10') }}
+      if: ${{ !(matrix.python-version == '3.9') }}
       run: |
         locale
         pytest -n auto --cov=psyclone --cov-report=xml src/psyclone/tests
     - name: Test with pytest and C Locale
-      if: ${{ matrix.python-version == '3.10' }}
+      if: ${{ matrix.python-version == '3.9' }}
       run: |
         locale
         pytest -n auto --cov=psyclone --cov-report=xml src/psyclone/tests
diff --git a/src/psyclone/psyir/frontend/fparser2.py b/src/psyclone/psyir/frontend/fparser2.py
index d95d520820..a8af08d570 100644
--- a/src/psyclone/psyir/frontend/fparser2.py
+++ b/src/psyclone/psyir/frontend/fparser2.py
@@ -44,7 +44,7 @@
 from dataclasses import dataclass, field
 import os
 import sys
-from typing import Iterable
+from typing import Iterable, Optional
 
 from fparser.common.readfortran import FortranStringReader
 from fparser.two import C99Preprocessor, Fortran2003, utils
@@ -974,9 +974,9 @@ class SelectTypeInfo:
             'class default' clauses, or -1 if no default clause is found.
 
         """
-        guard_type: list[str | None] = field(default_factory=list)
-        guard_type_name: list[str | None] = field(default_factory=list)
-        intrinsic_type_name: list[str | None] = field(default_factory=list)
+        guard_type: list[Optional[str]] = field(default_factory=list)
+        guard_type_name: list[Optional[str]] = field(default_factory=list)
+        intrinsic_type_name: list[Optional[str]] = field(default_factory=list)
         clause_type: list[str] = field(default_factory=list)
         stmts: list[list[StmtBase]] = field(default_factory=list)
         selector: str = ""
diff --git a/src/psyclone/psyir/symbols/datatypes.py b/src/psyclone/psyir/symbols/datatypes.py
index 4696d16104..94ff9127cd 100644
--- a/src/psyclone/psyir/symbols/datatypes.py
+++ b/src/psyclone/psyir/symbols/datatypes.py
@@ -43,7 +43,7 @@
 from collections import OrderedDict
 from dataclasses import dataclass
 from enum import Enum
-from typing import Any
+from typing import Any, Optional, Union
 
 from psyclone.configuration import Config
 from psyclone.errors import InternalError
@@ -109,7 +109,7 @@ def reference_accesses(self):
         return VariablesAccessMap()
 
     @property
-    def is_allocatable(self) -> bool | None:
+    def is_allocatable(self) -> Optional[bool]:
         '''
         :returns: whether this DataType is allocatable. In the base class
             set this to be always False.'''
@@ -124,7 +124,7 @@ def __str__(self):
         return "UnresolvedType"
 
     @property
-    def is_allocatable(self) -> bool | None:
+    def is_allocatable(self) -> Optional[bool]:
         '''
         :returns: whether this DataType is allocatable. In case of an
             UnresolvedType we don't know.'''
@@ -354,7 +354,7 @@ def reference_accesses(self):
         return access_info
 
     @property
-    def is_allocatable(self) -> bool | None:
+    def is_allocatable(self) -> Optional[bool]:
         '''If we have enough information in the partial_datatype,
         determines whether this data type is allocatable or not.
         If it is unknown, it will return None. Note that atm PSyclone
@@ -1101,7 +1101,7 @@ class ComponentType(CommentableMixin):
         :type initial_value: Optional[:py:class:`psyclone.psyir.nodes.Node`]
         '''
         name: str
-        datatype: DataType | DataTypeSymbol
+        datatype: Union[DataType, DataTypeSymbol]
         visibility: Symbol.Visibility
         initial_value: Any
 
diff --git a/src/psyclone/tests/psyir/transformations/transformations_test.py b/src/psyclone/tests/psyir/transformations/transformations_test.py
index 22b7d6454a..f743399e92 100644
--- a/src/psyclone/tests/psyir/transformations/transformations_test.py
+++ b/src/psyclone/tests/psyir/transformations/transformations_test.py
@@ -40,6 +40,7 @@
 API-agnostic tests for various transformation classes.
 '''
 
+import sys
 import os
 import pytest
 from fparser.common.readfortran import FortranStringReader
@@ -590,11 +591,16 @@ def test_omploop_trans_new_options(sample_psyir):
 
     with pytest.raises(TypeError) as excinfo:
         omplooptrans.apply(tree.walk(Loop)[0], collapse="x")
-    assert ("'OMPLoopTrans' received options with the wrong types:\n"
-            "'collapse' option expects type 'int | bool' but "
-            "received 'x' of type 'str'.\n"
-            "Please see the documentation and check the provided types."
-            in str(excinfo.value))
+    if sys.version_info >= (3, 10):
+        assert ("'OMPLoopTrans' received options with the wrong types:\n"
+                "'collapse' option expects type 'int | bool' but "
+                "received 'x' of type 'str'.\n"
+                "Please see the documentation and check the provided types."
+                in str(excinfo.value))
+    else:
+        assert ("The 'collapse' argument must be an integer or a bool but got"
+                " an object of type <class 'str'>"
+                in str(excinfo.value))
 
 
 def test_omplooptrans_apply_nowait(fortran_reader, fortran_writer):