See the comments for explanation:

#!/usr/bin/perl
use strict;
use warnings;
use feature 'say';

my $last = '';                                    # Remember the id.
my $count_1_x;
my $count_nonblank;
while (<DATA>) {
    my ($id, $col2, $col3) = split;
    if ($id ne $last) {                           # A new record begin
+s.
        say "$last $count_1_x $count_nonblank"
            if $last;                             # Do not print at th
+e very beginning.
        $last = $id;
        $count_1_x = $count_nonblank = 0;
    }
    $count_1_x++      if '1_x' eq $col2;
    $count_nonblank++ if defined $col3 and length $col3;
}
say "$last $count_1_x $count_nonblank" if $last;  # Print for the last
+ record.

__DATA__
A 1_x 9_z
A 1_x 
A 1_x g_z
B 2_c 
B 1_x 1_z
C 1_x 1_z
C v_x 8_z 
D v_x s_x
E 1_x 
F
[download]

Update: Updated to comfort warnings on emtpy column 3.

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