QUESTION 1:
Can a Jumuah (Friday prayer) be delayed or postponed? The Imam who is suppose to give the sermon is coming late. Jumuah should start at 1pm but Imam came at 1.45pm.
QUESTION 2:
During the sermon, can the worshipers shouted "Allahuakbar! Allahuakbar! and "you tell them!"
Can the worshipers make such "noises" while the listening to the sermon?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

The Sunnah in regard to the Friday prayer is to perform it directly after the sun passes the meridian, as it is confirmed that the Prophet used to pray the Friday prayer when the sun passes the meridian. [Al-Bukhari] Therefore, it is more appropriate for you to try to comply with the Sunnah as much as possible and try to perform it early. However, if you delay it, then the prayer is valid and you are not sinful as long as its time is not ended. Indeed, its time ends by the beginning of the time of ‘Asr.

As regards the congregation saying “Allaahu Akbar” during the Khutbah (the Friday speech) and saying to the preacher “you tell them”, then saying that during the Khutbah is not from the Sunnah; rather, this is contrary to the Sunnah which urged us to listen and not speak during the Khutbah.

Indeed, the scholars stated that it is forbidden for anyone to talk during the Khutbah except the Imaam or whoever speaks to the Imaam for a benefit, and that the congregation are obliged to listen to the Khutbah.

The Permanent Committer of Fatwa stated that if the Imaam orders the congregation to raise their voice with Tahleel [saying Laa Ilaaha Illa Allaah, i.e. None has the right to be worshipped except Allaah], Takbeer [saying Allaahu Akbar], then this is a religious innovation.

Allaah Knows best.