There's a blog about porting the arcade (Z80) code of Pac Man to the 6809 Color Computer. This link is about converting the Z80 to 6809 but elsewhere is discussion of blitting, ie drawing the sprites with the CPU to a bitmap, and I think he ended up using a similar technique IIRC
https://nowhereman999.wordpress.com/2016/12/29/zilog-z80-to-...You can definitely try that one.