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