Unfortunately no. You can take the 1Z0-809 exam, but even if you pass you won't received the certification title from Oracle. You have two options:
1) Take the OCP 7 exam (1Z0-804), then take the OCP 8 upgrade exam (1Z0-810)
2) Take the OCA 8 exam (1Z0-808), then take the full OCP 8 exam (1Z0-809)
There's an on-going debate on the forums about which path you should chose, but I recommend #2. And not because (full disclosure) I wrote a book on each exam. The 1Z0-804 and 1Z0-810 exams will both be quite difficult since they are OCP exams, whereas at least the 1Z0-808 OCA 8 exam should be easier for you since you already passed the 1Z0-803 exam. Also, the OCA 8 exam should be a nice warm up to lambdas that you will need to know for the OCP 8 exam.
In other words, I would focus on taking the OCA 8 and knocking that out quickly. If you successfully passed the OCA 7 exam, you have very little to learn to pass the OCA 8 exam. On the other hand, the OCP 8 exams (all of them) require a lot of studying!
Like Scott, I'm biased because we wrote books for Java 8.
If you are in a big hurry to get an OCP cert, I recommend taking path one (OCP 7). If not, I recommend path two (OCA 8). In addition to being an easier path, the OCP 7 covers some topics that Oracle thought better of and removed from the OCP 8. So you are learning content that isn't on the exam or used much in the real world (like listening for changes on the file system.)