I want to show payment data on a visual force page. I cannot get this to work. I am thinking that I have correctly queried through a nested relationship statement and all is well, but this is not happening.  The visualforce page is here: 
   

<apex:page controller="TestRollUpData">
    <apex:form >
        <apex:pageBlock title="Tests" id="more_tests">
			<apex:pageBlockTable value="{! Opportunity }" var="o">
                <apex:column value="{! o.Name}"/>
                <apex:column value="{! o.Designated_Fiscal_Year__c}"/>
                <apex:column value="{! o.Amount}"/>
            </apex:pageBlockTable>
            <apex:pageBlockTable value="{! o.npe01__OppPayment__r }" var="x">
                <apex:column value="{! x.npe01__Payment_Date__c}"/>
            </apex:pageBlockTable>
            <apex:repeat value="{! Opportunity }" var="x">
              <script>
                  document.getElementById('totalRevenue').value =
                 parseFloat(document.getElementById('totalRevenue').value) + {! Opportunity.Amount};
              </script>
            </apex:repeat>
        </apex:pageBlock>
    </apex:form>
</apex:page>

and the controller is here:
 

public class TestRollUpData {
    

   
    public List<Opportunity> getOpportunity(){ 
    
         List<Opportunity> tests = [SELECT Name, Amount, Designated_fiscal_year__c,
                                    (SELECT npe01__Payment_Date__c FROM  npe01__OppPayment__r ) FROM Opportunity 
            WHERE Designated_fiscal_year__c = '2020-2021' LIMIT 10];	
           
           return tests;
           
         }
    
    }

​Does anyone have any idea if this is because my npe01__OppPayment__r field is reference NPSP managed fields and is not standard Salesforce payment or is this just a bad query? I think theoretically this makes sense. Why will this not show on the page? The only error I'm getting is Unknown property 'TestRollUpData.o'. On my TestRollUpData page and controller.

Thanks.