The full text of SG9 reads as follows:
<SG9> Keep Scoring Objects in the field. Teams may not intentionally remove Scoring Objects from the field. While Scoring Objects may accidentally leave the field, doing so intentionally or repeatedly would be a violation of this rule. Scoring Objects that leave the field during Match play, intentionally or unintentionally, will be returned to the field at the location nearest the point at which they exited. Referees will return the Scoring Object to the field when it is deemed safe to do so, at the leisure of the referee.
Minor violations of this rule that do not affect the Match will result in a warning. Match Affecting offenses will result in a Disqualification. Teams that receive multiple warnings may also receive a Disqualification at the Head Referee’s discretion.
If a Mobile Goal leaves the field, any Rings that were Scored in the Mobile Goal Base, or on Mobile Goal Branches, will be returned to the field in a non-Scored state, on the field tile closest to where they exited.
Note: During the last 30 seconds of the Match:
• Any Scoring Object that leaves the field will not be returned.
• If a Scoring Object is leaving the Field (as determined by the Head Referee), but is deflected back into the field by a Drive Team Member, field monitor, ceiling / wall, or other external factor, it should still be considered “out of the field” and removed by a scorekeeper or Head Referee. If the redirection occurred due to contact with a Drive Team Member, it will be at the Head Referee’s discretion whether <G9> or <SG9> should apply.
The intent of the Note's second bullet point is to say that as soon as a Scoring Object makes contact with anything outside of the field, it should be considered "out of the field" and dealt with accordingly.
Therefore, the Mobile Goal in the attached image should be considered "out of the field". If the contact occurred during the last 30 seconds of the Match, it should be removed from the field. If it cannot be removed from the field safely and/or in a timely manner, it should simply be considered "not scored".
If the contact occurred before the last 30 seconds of the Match, then the Mobile Goal should be returned to a field tile closest to where it exited. It should not be returned to a Platform.