PowerShell ‘Or’ Statement

The operator is -or, not or. See about_Logical_Operators. Also, if statements don’t read from the pipeline. Either put the if statement in a ForEach-Object loop:

... | ForEach-Object {
  if ($_.extensionattribute9 -eq 'Smith, Joe' -or $_.extensionattribute9 -eq 'Doe, John') {
    $_ | select extensionsattribute9, country
  }
}

or use a Where-Object statement instead:

... | Where-Object {
  $_.extensionattribute9 -eq 'Smith, Joe' -or
  $_.extensionattribute9 -eq 'Doe, John'
 } | Select-Object extensionsattribute9, country

And you can’t use property names by themselves. Use the current object variable ($_) to access properties of the current object.

For checking if an attribute has one of a given number of values you can also use the -contains operator instead of doing multiple comparisons:

'Smith, Joe', 'Doe, John' -contains $_.extensionattribute9