Hoppes #9 isn't specific enough since it's not just a product but a brand of lots of products. What I know is that S&W has advised against anything abrasive. I believe they have also advised against cleaners containing ammonia. The MSDS for Hoppes #9 Bore Solvent indicates it contains ammonium hydroxide. If you're not sure about any other Hoppes #9 product, check it out here:
http://www.hoppes.com/global/customer-service/sds-information
We know that the traditional Hoppes #9 product is mostly kerosene and there is no reason to be concerned if a Ti cylinder was cleaned with it once. What I would be more concerned about would be the strong ammonia copper solvent bore cleaners. If you want a recommended cleaner going forward, avoid those with ammonia. Use Hoppes Elite for example, or Breakfree, or Ballistol etc.