The CEO is not going to be looking at individual risk logs. You need to look at the agenda and minutes of board meetings to see if it's being discussed. You can ask to make a presentation or report to the board on your progress on that big Excel, the overall status of the school, and the top 5 urgent items.I am able to log in and check who has looked at it and the CEO, who is well aware of its existence, has not once looked at it.
The reaction to your request will tell you everything you need to know. If you get told "no need", you'll know not only is the board ignoring issues, but that they are ignoring them with plausible deniability (meaning they know issues have to be fixed, and if they were officially aware of them then they would have to fix the issues, so they are making sure that they are not officially aware).
You can then ask to submit a report for consideration by the board, make sure it's on the agenda, and check the minutes that it has been at least acknowledged, and at best, discussed.
If not, rinse and repeat.