US citizen wanting long stay in UK

[JaneUK]

Hello, can you help? If a US citizen, retired, of independent means, wants to come on holiday to the UK for longer than the 6 months allowed without visa, how easy is it for him to get a visitor's visa to stay for, say, 9 months?

[CR001]

A visitor cannot stay in the UK for more than 6 months and cannot stay in the UK for longer periods than you stay in your home country.