The suspension will expire on June 6, crucially meaning the 2005 Lions wing will be free to play in the World Cup and all of England's warm-up matches.
The Rugby Football Union judged his actions to be a mid-range offence with a normal sanction of 18 weeks but halved the ban after Cueto's "compelling mitigation".
"At the hearing Cueto did not contest the citing and he was suspended for nine weeks," read a RFU statement.
"The suspension runs from April 4 to June 6, 2011 and he can resume playing on June 7, 2011.
"The panel decided that this was a mid-entry offence, which attracts a ban of 18 weeks, but because of the player's compelling mitigation he received the full 50 per cent discount."
Cueto had already been banned by his club Sale, following the incident which occurred during the Sharks' 53-24 Premiership defeat by Northampton earlier this month.
The Lion's ban was back-dated to April 4, the day he was handed the six-week internal suspension.
He will sit out the remainder of the domestic season and will link up with England on June 20 ahead of their World Cup warm-up matches with Wales and Ireland in August.