line9OpeningDate

Given a predicate that represents a relationship or action between entities, generate a one-sentence description explaining its meaning.  
# Instructions
Focus on describing the relationship, not the entities themselves. 
# Response Format
Begin the description with \' Indicates...\'

Predicate: line9OpeningDate

Indicates the date on which line 9 (e.g., a route, service, or infrastructure segment) was officially opened or began operation.