I put my wort in the primary 9 days ago and dry hopped with 1 ounce of Cascade pellets and used a Wyeast 1272 American direct pitch activator pack. I have not taken any readings but noticed it was still bubbling at about 1 per minute. This is much longer than in the past. My question is can I dry hop and add to a secondary or should I wait a little longer.
Airlock bubbles don't really tell you anything about the state of fermentation. They only indicate CO2 is being released and that can come from a number of reasons. A gravity reading is really the only way to know what's going on. That said, 9 days is a pretty short time for primary. I usually wait at least 2-3 weeks before I even check on the gravity. There's no harm to letting the beer go longer and at the very least the yeast will have more time to finish and clean up after itself. And if you want to, you can skip the secondary entirely. I seldom do one.
How long to leave in primary is a controversial topic, but the current thinking is to err on the side of leaving it in longer. The rule of thumb I use for my brews is four weeks minimum in primary. Some of my higher gravity brews I will leave in for 8 weeks. I only use secondaries for things that require very extended aging, like barleywines.
For something like an IPA that is consumed more fresh, I probably would leave it in primary for no less than two weeks, then secondary for dry-hopping. Your milage may vary, of course.
In general if you have a good pitch rate and and good aeration, primary fermentation can finish up relatively quick (4-10 days). As stated above, leaving it in the primary fermenter for a bit will help to start cleaning up the beer.
As Denny commented, it is possible it is still bubbling due to under-pitching, or maybe not getting a good level of oxygen into the wort before pitching.
The question is then if you should put it into secondary or not. Some sources I have seen even say that it may not be worth the extra risk of contamination moving it to secondary, and you can even leave it sit in the primary for an extra week or two to let the yeast settle out, then just package it. It all depends on what you are doing, but I do agree, if you can get away with leaving it in the primary for a bit, why risk the contamination by racking it over?
Just a few things to think about.