with tab_s as ( select to_date('09.11.2016', 'dd.mm.yyyy')+1  /* если считаешь что 8 - то убери +1*/ a  
                     , to_date('01.01.2014', 'dd.mm.yyyy') b from dual ),
     tab as ( select a, b, months_between( a, b ) dt from tab_s )

  select trunc( dt / 12 ) || ' лет ' || mod( trunc( dt ), 12 ) || ' месяцев ' ||
         case when extract( day from b ) > extract( day from a )
              then greatest( extract( day from last_day( add_months(a, -1) ) ), extract( day from b ) ) +
                   extract( day from a ) - extract( day from b )
              else extract( day from a ) - extract( day from b )           
            end || ' дней' dt
          from tab;

DECLARE
  DateS   DATE := TO_DATE('01.01.2014','dd.mm.yyyy'); 
  DatePo   DATE := TO_DATE('09.11.2016','dd.mm.yyyy')+1; 
  Days_cnt    NUMBER;
  Months_Cnt  NUMBER;
  Years_Cnt   NUMBER;
  Y_string VARCHAR2(4):='лет';
  M_string VARCHAR2(10):='месяцев';
  D_string VARCHAR2(10):='дней';
                                       
BEGIN


  Months_Cnt := mod( trunc( months_between(DatePo,DateS) ), 12 );
  Years_Cnt  :=  trunc( months_between(DatePo,DateS)/12);

  IF  EXTRACT( DAY  FROM  DateS ) > EXTRACT( DAY FROM DatePo )
              THEN  Days_cnt:= GREATEST( EXTRACT( DAY FROM last_day( add_months(DatePo, -1) ) ), EXTRACT( DAY FROM  DateS ) ) 
                +  EXTRACT ( DAY  FROM  DatePo ) - EXTRACT ( DAY  FROM  DateS );
              ELSE Days_cnt:= EXTRACT( DAY FROM DatePo ) - EXTRACT( DAY FROM  DateS );
                END IF;


dbms_output.put_line('года='||Years_Cnt);
dbms_output.put_line('месяцs='||Months_Cnt);
dbms_output.put_line('дни='||Days_cnt);

------YEARS----------
      IF (MOD(Years_Cnt,
              10) = 1) AND
         (Years_Cnt NOT IN (11,111,211,311,411,511))
      THEN
        Y_string := 'год ';
      ELSIF (MOD(Years_Cnt,10) IN (2,3,4)) AND
            (NOT (Years_Cnt IN (12,13,14)))
      THEN
        Y_string := 'года';
      ELSE
        Y_string := 'лет';
      END IF; 

---------MONTHS--------
      IF Months_Cnt = 1
      THEN
        M_string :=  'месяц';
      ELSIF (Months_Cnt IN (2,3,4))
      THEN
        M_string :=  'месяца';
      ELSE
        M_string := 'месяцев';
      END IF;

   -------DAYS---------- 

      IF (MOD(Days_cnt,100) IN (11,12,13, 14)) OR
         (MOD(Days_cnt,10) NOT IN (1,2,3,4))
      THEN
        D_string :='дней';
      ELSIF (MOD(Days_cnt,10) = 1)
      THEN
        D_string :=  'день';
      ELSE
        D_string := 'дня';
      END IF;

   ----------------- 

dbms_output.put_line('-----------------' );
dbms_output.put_line(Years_Cnt||' '||Y_string||' '||Months_Cnt||' '||M_string||' '||Days_cnt ||' '||D_string );
END;