Check your employer's contract to see if you are allowed to work on personal project during off hours.
You can still work on an idea you're passionate about if you can manage your time efficiently.
Another way is to find a capable co-founder and he can be the solo founder to get in the program, while you both can become co-founders when your idea gains traction and you've decided to incorporate.
I would also recommend leaving your contact information in your HN about page so that people can contact you about co-founding a startup.
You can still work on an idea you're passionate about if you can manage your time efficiently.
Another way is to find a capable co-founder and he can be the solo founder to get in the program, while you both can become co-founders when your idea gains traction and you've decided to incorporate.
I would also recommend leaving your contact information in your HN about page so that people can contact you about co-founding a startup.