>perl -wMstrict -le
"my $string = '9 9 0:00 11/21/2012 12:34 01/23/2012 9 9';
 print qq{'$string'};
 ;;
 my $time = qr{ (?<! \d) \d{1,2} : \d{2}       (?! \d) }xms;
 my $date = qr{ (?<! \d) \d{2} / \d{2} / \d{4} (?! \d) }xms;
 ;;
 $string =~ s{ $time \K [ ] (?= $date) }{   }xmsg;
 print qq{'$string'};
"
'9 9 0:00 11/21/2012 12:34 01/23/2012 9 9'
'9 9 0:00   11/21/2012 12:34   01/23/2012 9 9'