I'm trying to host a dueling match between me and a druid who are out for blood, I''m a sorcerer lv 8 vs a level 8 druid, Im really new and the druid has a core group they play with every week. the druid keeps healing by shapeshifting. what spells should my sorcerer use to stop the druid?

is their a way to use higher tier spells above my level?

Probably won't land since it's the strongest save and you probably didn't pick it since it's usually a terrible spell, but just having the druid know that you have dominate beast available would be a pretty effective way to encourage a druid not to shapeshift.

Dominate Beast would require a ruling. It may or may not work against a Druid who is in Wild Shape because they’re still a Druid in the shape of a beast. But it would definitely work against a Druid who has cast Polymorph on himself. 

Something important about Wild Shape. A Druid can only do it twice per rest until level 20, so after a Druid uses Wild Shape twice to regain their hit points they’re stuck in their normal form.