The U.S. freestyle wrestling team had a perfect 4-0 morning during the 9:30 session at the Olympic Games, held at the Sydney Exhibition Centre in Darling Harbour, September 29.     Two U.S. wrestlers qualified for the semifinals,  Sammie Henson (Norman, Okla./Sunkist Kids) at 54 kg/119 lbs. and Brandon Slay (Amarillo, Texas/Dave Schultz WC) at 76 kg/167.5 lbs., after victories in the quarterfinal round. Both have clinched at least a top-four finish in their weight divisions and will be in the medal matches.    Henson scored a spectacular 8-4 comeback win over 1999 World bronze medalist Oleksandr Zakharuk of Ukraine. Zakharuk scored the first takedown at 42 seconds, then launched Henson with a three-point arm throw at 1:12 for a 4-0 lead. Henson scored a single leg takedown at 2:37 to close it to 4-1 at the break. Henson opened the offense, scoring a single leg at 3:25, then scoring a tilt and hold for three more points for a 5-4 lead. Henson added a spin behind takedown for a 6-4 lead and another tilt for two points at 5:30 for the deciding 8-4 win.    Henson was a 1998 World champion and is competing in his first Olympics. He will face German Kontoev of Belarus in the semifinals.    Slay had a difficult quarterfinal match, scoring a 2-2 overtime referee's decision over Gennadiy Laliyev of Kazakhstan. The difference was fewer passivities against Slay. Slay scored the first takedown at 2:26 for a 1-0 lead, then was reversed by Laliyev for a 1-1 tie. In the second period, Slay hit a double leg takedown for a 2-1 win at 3:23. Regulation ended at 2-1, but Laliyev tied it up at 2-2 at 6:33 with a takedown. No more points were scored.     Slay, who is competing in his first Olympic Games and his first Senior World level event, advances to the semifinals where he faces 1999 World bronze medalist Adem Bereket of Turkey. Bereket beat American Joe Williams in the 1999 World bronze medal match.    Two other U.S. wrestlers won the opening match of their pool competitions, Lincoln McIlravy (Iowa City, Iowa/Gateway WC) at 69 kg/152 lbs. and Kerry McCoy (Bethlehem, Pa./New York AC) at 130 kg/286 lbs.    McIlravy won his first match, scoring an injury default over Ibo Oziti of Nigeria. The first period was scoreless, and Oziti won the clinch position for a caution and one point lead. McIlravy quickly tied the bout with a spin behind takedown, then took a 2-1 lead at 4:25 on a low single takedown. Oziti took an injury time out, rotated his left shoulder a bit, then took an injury default loss at 4:37.    McIlravy was a 1999 World silver medalist and a 1998 World bronze medalist. He will have a bye in the evening session.    McCoy scored a 3-0 overtime win over past World medalist Merabi Valiyev of Ukraine. McCoy got his first point on a fleeing the mat call at 2:12. He added a single leg takedown in the second period at 5:58. He closed the bout down at 8:33 with another takedown.     McCoy was fourth in the 1998 World Championships. He will have a bye in the evening session.    Two U.S. wrestlers drew byes in the first session and will have their first matches this evening: Terry Brands (Lincoln, Neb./Sunkist Kids) at 58 kg/127.75 lbs. and Charles Burton (Bloomington, Ind./New York AC) at 85 kg/187.25 lbs.    Freestyle Wrestling, September 29, 9:30 a.m.    54 kg - Sammie Henson, Norman, Okla. (Sunkist Kids)    Quarterfinals - dec. Oleksandr Zakharuk (Ukraine), 8-4    58 kg - Terry Brands, Lincoln, Neb. (Hawkeye WC)    No matches this session    69 kg - Lincoln McIlravy, Iowa City, Iowa (Gateway WC)    won by inj. dft. over Ibo Oziti (Nigeria), 4:37    76 kg - Brandon Slay, Amarillo, Texas (Dave Schultz WC)    Quarterfinals - won by ref. dec. over Gennadiy Laliyev (Kazakhstan), 2-2, ot, 9:00    85 kg - Charles Burton, Bloomington, Ind. (New York AC)    No matches this session    130 kg - Kerry McCoy, Bethlehem, Pa. (New York AC)    dec. Merabi Valiyev (Ukraine), 3-0, ot, 8:33