One thought—whether the WTS would ever agree with it or not does not matter.
At Acts 18:24-5 there is a report about Apollos going from Alexandria, Egypt to Ephesus, Asia Minor (= Turkey) where he preached about Jesus on the basis of John the Baptist's testimony. It states that Priscilla and Aquila corrected him a bit (v. 26). Now if Jesus was known down in Egypt through the work of John the Baptist, then surely he was as well in Judea/Palestine also via John's disciples. That John had his own disciples is clear from Luke 7:18-20 and John 4:1. At least one of them became the apostle Andrew (John 1:35-40).
If we go back to Acts again, we see Paul finding a group of 12 disciples of John in Ephesus and rebaptizing them as disciples of Jesus (19:1-17). So John's disciples were in various places. That he was not an unknown figure is also clear from Josephus speaking about him.
Therefore, with all these references to John and his disciples, it seems likely that those mentioned in Luke 9 were disciples of John. Those you ask about were then disciples of John the Baptist who were speaking of Jesus. Since Jesus and John were on the same page, it should be no surprise that Jesus told his disciples to leave them alone. Whether they would ever convert to being one of his disciples, Jesus probably just let occur or not.