Just to find next number of the sequence 9,27,54,117,243,504,1017,2043

I can't find the next term here, but the fact that every digit within each number adds up to nine may be a hint.

Also, you can notice that you have 54, 117, 243... then 504, 1017, 2043, the zero being put in between the first and second digits... but that seems to lead no nowhere...

This sequence is a most strange one... I'd really like to solve it...

So far the closest pattern seem to be '(x2) + 9' but it doesn't work for the third and sixth terms.