Different Bibles number the Psalms in different ways. Some split Psalm 9 in two, making it 9 and 10. These same versions also combine Psalms 146 and 147, so the total number of Psalms remains 150. The practical upshot of this is that between psalms 8 and 148 the number may be off by one, depending on what version you’re looking at. Therefore, if you look up a Psalm reference and it doesn’t seem to fit what is being talked about, try looking one psalm earlier or later, and you’ll probably find the right place.