Compare Column and highlight difference

You can use Conditional Formatting with two rules

Conditional Formatting

• Highlight applicable range >> $B$9:$F$116
• Home Tab >> Styles >> Conditional Formatting >> New Rule
• Select a Rule Type: Use a formula to determine which cells to format
• Edit the Rule Description: Format values where this formula is true: =B9<>I9
• Format… [Number, Font, Border, Fill] Select Fill >> Red
• OK >> OK

• Highlight applicable range >> $I$9:$M$116
• Home Tab >> Styles >> Conditional Formatting >> New Rule
• Select a Rule Type: Use a formula to determine which cells to format
• Edit the Rule Description: Format values where this formula is true: =I9<>B9
• Format… [Number, Font, Border, Fill] Select Fill >> Red
• OK >> OK

Try...

Sub ApplyCF()
    Dim wsSrc As Worksheet: Set wsSrc = Sheets("Reconciliation_Summary")
    Dim LastRow As Long: LastRow = wsSrc.Range("A" & Rows.Count).End(xlUp).Row
    Const Fm1$ = "=B9<>I9"
    Const Fm2$ = "=I9<>B9"
    Const CellColor = 9
    Const FontColor = 2

    Application.ScreenUpdating = False
    With wsSrc.Cells
        With .FormatConditions
            .Delete
        End With
    End With

    wsSrc.Range("B9").Select
    With wsSrc.Range("B9:F" & LastRow)
        With .FormatConditions
            With .Add(Type:=xlExpression, Formula1:=Fm1)
                .Interior.ColorIndex = CellColor
                .Font.ColorIndex = FontColor
            End With
        End With
    End With

    wsSrc.Range("I9").Select
    With wsSrc.Range("I9:M" & LastRow)
        With .FormatConditions
            With .Add(Type:=xlExpression, Formula1:=Fm2)
                .Interior.ColorIndex = CellColor
                .Font.ColorIndex = FontColor
            End With
        End With
    End With
    
    Application.ScreenUpdating = True
End Sub

jeffreybrown,

Thanks for the code, I will check and get back to you tomorrow. I am out of office.

You are very welcome. Happy to help.