Well, Yes and No.
If we look a couple verses down we read this:
2 Corinthians 9:10-11 (NIV)
10 Now he who supplies seed to the sower and bread for food will also supply and increase your store of seed and will enlarge the harvest of your righteousness. 11 You will be enriched in every way so that you can be generous on every occasion, and through us your generosity will result in thanksgiving to God.
We see two concepts at play here:
- (v10) God
will enlarge your harvest of righteousness
You will be enriched in every way so that you can be generous on every occasion.
This passage in this letter seems to be indicating that if you give to the poor, God will make sure that you have enough to live off of and continue to give. Furthermore, it shows that God will reward your giving with a "harvest of righteousness".
So, will God make you rich?
He will make sure that you have enough so that you can keep on giving, though. He will bless you in ways to make sure that you can continue to bless others. But that mark is far short of anyone's definition of "rich". However, God will continue to provide for your needs.
This concept harkens back to Jesus word's in Matthew 6:26
Matthew 6:26 (NIV)
Look at the birds of the air; they do not sow or reap or store away in barns, and yet your heavenly Father feeds them. Are you not much more valuable than they?