Slightly off the mark.
Kenya actually attained independence on 1 June 1963
but was only formally declared a republic on 12 December 1964 ( Bureaucracy ? )
Birth Cert Forms were almost certainly printed pre Dec 1964
The key is to find evidence/proof of the date
that his Father and Mother moved to Hawaii
There must be a flight log somewhere ?
Hawaii airport passport checks ? Where did they stay after landing ?