Again, I'm not going to fall into your literalist trap. You seemed to think a simple yes/no was all that was required. As I have demonstrated, that is not the case since you starting interpreting the matter according to your hermeneutical biases.
The high priest "saw" Jesus' coming to judge Israel for killing the Messiah, just has He predicted.
"Therefore, indeed, I send you prophets, wise men, and scribes: some of them you will kill and crucify, and some of them you will scourge in your synagogues and persecute from city to city, that on you may come all the righteous blood shed on the earth, from the blood of righteous Abel to the blood of Zechariah, son of Berechiah, whom you murdered between the temple and the altar. Assuredly, I say to you, all these things will come upon this generation." (Matt. 23; cf Matt. 27:25)
Not every coming in the Bible is the "second coming". For example, Jesus said, "Assuredly, I say to you, there are some standing here who shall not taste death till they see the Son of Man coming in His kingdom." Now, either this was fulfilled in the 1st century, or there are 2000 year old folks running around the world somewhere who will still be alive when Jesus returns.
Yes, Jesus came in AD70 and fulfilled the passage. No, it was not the "second coming".
Do you have any proof that the high priest wasn't dead by 70AD? The high priest was most likely an elderly man. The position of high priest is not one given to youngsters, but was reserved for patriarchs. And given that the average lifespan back then was close to 50 years of age, the odds of the high priest living to AD 70 was slim and none.
You are grasping at straws to assume that the high priest was there to witness the return of Jesus dressed up as the Roman Army. While God may have executed judgment upon the Nation of Israel in 70AD, this was not the return of Christ. The High priest will someday see Jesus on the right hand of the Father and will someday see him coming with clouds. Every knee shall bow. Not now, but then.