I am not sure on this, but I believe I heard someone say that Innervate can't be cast at full mana, which would mean that it to trigger Excess Mana. This would also be the case with The Coin. I believe only cards that grant permanent mana crystals like Wild Growth and Nourish can be used to trigger Excess Mana.
Permanent Mana Gains through cards like Wild Growth will draw a card for each mana crystal it was supposed to give you.
Temporary Mana Gains through cards like Innervate will only refill empty mana crystals. I think a safe assumption can be made, you are either unable to play Innervate when you're at 10/10 mana, or it will just disappear into the Nether.