Hi gnijs,
Option 1 is not very scalable.
With regards to option 2, SDA has three roles(well four if you include the control plane). Edge Node, Intermediate Node and Border/Default Border Node.
As you are aware, Intermediate nodes are just routed devices to provide reachability. However, if you use Catalyst 9000 (9500-24Q for example) as the intermediate node, it can also be an edge node. Therefore I would recommend you look at a design as follows:
9500-24Q (BN/DN/CP) ------ 9500-24Q (Intermediate/EN) ----- 9300 (ENs)
Hope this helps,
Liam