I have a retirement extension and re entry and O visa till 26th sept do to medical reasons I cannot arrive till 23rd sept two questions what date will i be singed in for and after my 14 days isolation can have I time to renew the extension or do I need to start again I still have the 800000 in the bank

When you enter the country immigration will ask you if you want to be stamped in to the September 26th or enter visa exempt that will allow 45 day permit to stay that can be extended for 30 days. In normal times you would normally have enough time to do the extension by the 26th but due to the quarantine you will need to accept the visa exempt entry.

You could then apply for a non-o visa at immigration shortly after you get out of quarantine. 

And then apply for the one year extension of stay during the last 30 days of the 90 day stay allowed by the visa.