Date AM/PM format - Logstash filter date parse error

Elastic Stack Logstash
1

I am having trouble on getting the filter date pattern match with my log file date pattern.
I want the date appears as EventDateTime attribute and date would be removed inside message field.
Anyone can help me, having trouble with setting up date with am/pm format.
Thanks.

my log file date format : 9/6/2016 3:46:01 AM

Below is my filter inside my config file

filter {
    grok {
        match => { "message" => "^(?<EventDateTime>%{MONTHNUM}/%{MONTHDAY}/%{YEAR} %{TIME}(?:AM|am|PM|pm))%{GREEDYDATA}" }
        }
    date {
            match => ["EventDateTime", "dd/MM/YYYY hh:mm:ss a"]
            #timezone => "UTC"
            #remove_field => ["EventDateTime"]
        }
}

Error Message

Pipeline main started
←[33mFailed parsing date from field {:field=>"EventDateTime", :value=>"9/6/2016
3:46:01", :exception=>"Invalid format: "9/6/2016 3:46:01" is too short", :conf
ig_parsers=>"dd/MM/YYYY hh:mm:ssa", :config_locale=>"default=en_US", :level=>:wa
rn}←[0m

{
       "message" => "9/6/2016 3:49:01 PM:Sending : FREE\r",
      "@version" => "1",
    "@timestamp" => "2016-09-06T09:43:52.052Z",
          "path" => "c:/logstash-tutorial/test1.trc",
          "host" => "test1",
          "tags" => [
        [0] "_grokparsefailure"
    ]
}