Heavy shelf... What fixings?

[SAM81]

I have a shelving unit I need to hang in the living room. Studs are too narrow for the shelf holes, so it's got to go straight on to the plasterboard. Shelf is around 9kg, unloaded. I'd guess it won't be too much heavier with what she wants to put on it

What fixings should I be looking at for this kind of weight on plasterboard?
Appreciated

 

[SAM81]

I really like these fittings for single thickness plasterboard on stud walls: https://www.screwfix.com/p/easyfix-hollow-wall-anchors-m5-x-52mm-100-pack/5643p

I used 6 to mount my TV. I only weigh 63kg on a good day and I lifted myself off the floor whilst holding on to the bracket.

P.S you can buy smaller packs. I would recommend buying the setting tool too: https://www.screwfix.com/p/setting-tool/12429

Perfect. Thanks!