Hi @Kris5
Yes it is possible. Let me explain how to do validation for creation hours in power automate. But i am not sure what you meant by clearing field, is it removing the item or updating that row name field as null/empty
well i have explained both cases below
For this purpose, i have created a list with one item like below

Case 1: when we need to update Name field as null/empty in row item.

So logic used is , getting all items from list, then looping through all items in list and then checking whether the item was created in list 8 hours before using the expression in condition
Expression used there is : int(formatDateTime(dateDifference(items('Apply_to_each')?['Created'],utcNow()),'HH'))
If the condition is true, we will be using update item to update the existing item by passing Name field as Null
2nd Case: when you need to delete list item which is created 8 hours before, made small change to existing flow

condition expression is same, only change is instead of update item, we have used delete item 🙂
Hope the information helps.
Here i have used recurrance flow concept to run the flow at scheduled time:)
Hope it helps 🙂
Mark it as solution if it resolves your query 🙂