Can an electronic ballast be used for a G23 lamp?
The given phototherapy tube is a glow start tube with filaments. The glow starter is built into the base. Glow start tubes are usually driven with conventional magnetic ballasts. There might be also electronic ballasts for 2 pin tubes with built in glow starters, but usually electronic ballasts need access to all 4 pins of the tube.

The given listing for "universal electronic ballast" is lacking in details (input voltage/frequency ranges, tube current etc.) to give any recommendation for it's suitability.

I'd recommend replacing the existing ballast with an European model. For example:
http://www.lighting.philips.com/main/prof/lighting-electronics/fluorescent/fluorescent-electromagnetic/bpl-em-ballasts-for-cfl-pl-t-pl-s-and-pl-c-lamps/913710122350_EU/product or https://www.helvar.com/en/products/L11D240V50Hz/ or any other magnetic ballast with correct frequency, voltage and lamp power. Also when converting the wires might need also upgrading for the higher mains voltage. Consult a local lamp repair shop for advice.

Added, since unable to comment:
Suitable search terms to try on your favorite online platform: "magnetic ballast 9w" "Helvar L11D" "pl-s ballast".