Whitelisting ip

[ytd]

Is it possible to whitelist my IP so that only i can access the service. If not, can i change the 'admin' account as i only have a sudo user and don't want to have unnecessary accounts open.

[skurudo]

Is it possible to whitelist my IP so that only i can access the service.

Yes, you can
/usr/local/vesta/nginx/conf/nginx.conf -- allow IP and deny for all other

If not, can i change the 'admin' account as i only have a sudo user and don't want to have unnecessary accounts open.

It's much harder, simple answer - no.