Make 'smart' USB Dedicated Charging Port
I can refer you to this question for some answers, How do I design a 2A or more power supply for my consumer USB devices?


  Probably any device I plug in with USB cable, might ask more than I can supply (since it's like a wall adapter) and could destroy my board?


On that particular subject, you are right. Assuming the device you plug in will follow the usb charging standards is not enough. I would strongly encourage you to, as good practice, implement at least overcurrent protection. With a ptc fuse for example.

I can additionally recommend that you look into the quite compact TPS2514A IC from TI, which can take care of advertising the 1A current limit you had in mind in a way that is compliant with the usb battery charging 1.2 specification (look in the datasheet, under Figure 16. 5-W USB Charger Application).