Is the hpv immunisation safe for girls aged 9? and would it be recommended for girls of this age?

Yes: The current (2018) Gardasil 9 helps develop protection against 7 strains of HPV associated with cervical cancer and 2 associated with genital warts. The vaccine is likely effective in any kid over 5 & hopefully given before any sexual exposure to HPV. The target age of 9-26 was driven by the US FDA approval process. The OBGyns I worked with gave it to their kids around 7.