can older people from outside london use their bus passes in london?

If you have a bus pass issued by your local council because you are senior citizen, then you can use the bus pass on any bus in the country regarded as public transport. As somone has previously said, this means you can use your bus pass on all public buses in London but does not include private run buses including the sightseeing buses.

You can only use the bus pass during off peak hours so only after 9.30am.

You will not be able to use any other form of London public transport i.e. tubes, trams, ferries for free.

Concessionary bus passes issued by English local authorities outside London are not valid on Tube, Tramlink, DLR, London Overground or National Rail Services, only buses with London Transport logo

Yes, but you might find them valid only between 09:30 and 04:30 the next day.

while you're a tourist, you need to purchase the 7-day bus bypass (countless rides) for 13 kilos. you do no longer would desire to take image or something - only pay up and get carry of it right this moment!

yes you can use it on the buses, but not on tube, train, tram etc ... and only "off peak" which really means before 9.30 in the morning

yes you can but not on the tourist buses