$re = '/.*[0-9]{2}9[0-9]{8}.*|.*[0-9]{2} 9 [0-9]{4} [0-9]{4}.*/m';
$str = 'EXEMPLOS QUE NÃO SÃO NÚMEROS DE TELEFONE (ZAP):
9999999999999999999999999999
119111111111
123456789123456789
EXEMPLOS NA PERGUNTA:
993345987
9 93345987
(21)932324343
(21)9 3232 4343
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php